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j^^'THE Brown-tail Moth
EUPROCTIS CHRYSORRHCEA (L.).
A REPORT ON THE
Life History and Habits of the Imported
Brown-tail Moth,
TOGETHER WITH A
DESCRIPTION OF THE REMEDIES BEST SUITED
FOR DESTROYING IT.
BY
Charles H. Feknald, A.M., Ph.D., and
Archie H. Kirkland, M.S.
Published under the Direction of the State Board or Agriculture,
BY Authority of the Legislature.
BOSTON :
WRIGHT & POTTER PRINTING CO., STATE PRINTERS,
18 Post Office Square.
1903.
-, •.. .'i^v^'V
' Approved by
The State Board of Publication.
Cammontotaltl^ ai S^assadjusetts.
Office of the Massachusetts State Board of Agriculture,
Boston, March 2, 1903.
I have the honor to submit herewith the special report
on the life history and habits of the imported brown-tail
moth (^Euproctis chiysorrhoea ) , prepared under authority
of chapter 42 of the Resolves of 1902. The work of pre-
paring this report was delegated to Prof. C. H, Fernald
and Mr. A. H. Kirkland, whose careful studies of the insect
have made them entirely familiar with its habits. It has
been the aim of the authors to present facts of practical
value to the property owner, rather than technical details ;
and it is hoped that the report will help our citizens to a
better understanding of the habits of the moth and methods
for destroying it.
Respectfully submitted,
JAMES W. STOCIvWELL.
I
THE BROWN-TAIL MOTH.
Nearly two centuries ago the famous French entomolo-
gist, Reaumur, wrote with delightful accuracy on the habits
and life history of a caterpillar, which, from its wide dis-
tribution and frequent occurrence, he called " /« commune,^*
— the common caterpillar. He described the strange habit
of the caterpillars in wintering half grown in a common
web ; their ravages in the spring in orchard and field ; and
their feedino- o;rowth and transformation into white moths
with bodies tipped with a golden band, — a marking that
at once explains the more familiar name, " the brown-tail
moth." This insect is indeed common in Europe, and
occurs wherever the pear and apple flourish. In England,
France and Germany its record is one of frequent damage
to fruit and shade trees, to shrubs and flowering plants ;
while at intervals it has appeared in prodigious numbers,
causing outbreaks that became matters of historical impor-
tance, and resulting in severe loss and grave alarm on the
part of afflicted property owners.
Such, in brief, is the brown-tail moth : in summer, a
snow-white, brown-tailed moth, laying its eggs on the
leaves of pear and many other trees ; in August, myriads
of tiny caterpillars, feeding on the tender foliage at the
tips of twigs ; in winter, hibernating safely in a tight silken
web ; in spring, sallying forth to complete their growth on
bud, blossom and leaf; in June, ending the life cycle in
cocoons from which the moths emerge by the middle of
July. A paragraph will give a synopsis of its known life
history ; a volume would not record its damage in the old
world, or the full importance of its unfortunate introduc-
tion into the new ; in fact, we do not know as yet just what
role this insect is to play in our horticultural operations,
6 THE BROW X-T AIL MOTH.
how many crops it will attack with severity, or how far it
w'ill spread.
In the present report we have attempted to give a plain
statement of what is known of the habits of this most inju-
rious and annoying insect, with remedies best suited for its
destruction . AVhile the authors have collaborated through-
out the entire w^ork, the parts pertaining to the European
history and the biology of the moth have been largely pre-
pared by Professor Fernald, while the history of the moth
in Massachusetts and the chapter on remedies have received
special attention from INIr. Kirkland. A large part of the
experiments on the moth, and nearly all the field observa-
tions on its habits, were made by us under the direction of
the gypsy moth committee in 1897-99 ; and to this com-
mittee, whose faithful labors have been of such signal value
to the State, we are specially' indebted for many favors in
connection wdth this report.
Discovery of the Moth.
In the spring of 1897 several residents of Somerville and
Cambridge, Mass., found a strange caterpillar feeding on
the unfolding leaves of pear trees. Apparently the insects
came from small, tough webs at the tips of the twigs, par-
ticularly at the tops of the trees. They worked downward,
consuming the foliage as they moved, and daily grew in
size. By the time the foliage was two-thirds developed, the
naked tree tops tipped with the gray abandoned webs were
conspicuous objects in the infested district. The outbreak
at that time was not widespread, but several thrifty prop-
erty owners noticed with alarm the inroads the insects were
daily making on the trees. When the damage by these
insects was first observed, the campaign against the gypsy
moth was being prosecuted vigorously under the auspices
of the State Board of Agriculture ; and the office of the
gypsy moth committee at Maiden naturally was regarded
as an information bureau on all matters pertaining to insect
depredations. Damage by the gypsy moth was well known,
and dreaded correspondingly. Property owners finding new
or strange insects on trees or crops frequently mistook them
THE BROWN-TAIL MOTH. 7
for gypsy moths, and requested information or help from
the committee, in order to suppress the insects.
In this way Mr. Joseph B. Pike, living at 51 Preston
Street, Somerville, Mass., noticing the work of the strange
caterpillar, on May 8, 1897, sent word to the office of the
gypsy moth, committee that an insect which he supposed to
be the gypsy moth was destroying his pear trees. This
complaint was promptly investigated by an agent of the
committee, Mr. Fletcher Osgood, who reported that an in-
sect, presumably the tent caterpillar, was at work on the
pear trees ; and Mr. Pike was advised to spray the trees
with some arsenical poison.
A second complaint of damage was received May 14 from
the well-known mycologist of Harvard University, Dr.
Roland Thaxter, and similar injury to pear trees was ob-
served. The unusual feature of a tent-making caterpillar at
work in the spring on pear trees aroused the interest of Mr.
Kirkland, at the time assistant entomologist to the gypsy
moth committee. Securing specimens, and not being able
to identify the insects oft' hand, he commenced to rear them,
in order that the species might be identified from the mature
moths. Following Dr. Thaxter's complaint concerning the
insect, other reports of damage came in rapidly to the. gypsy
moth ofiice, and in the course of a few davs it was evident
that an insect outbreak of extraordinary nature was taking-
place in Somerville and Cambridge. Specimens of the cat-
erpillar were given to Prof. C. H. Fernald, entomologist to
the committee, by Mr. Kirkland, who, being struck with the
similarity of the habits of the caterpillars to those of the
brown-tail moth as described in European literature, sug-
gested to Professor Fernald that this new insect might pos-
sibly be that notorious pest. On his return to Amherst
Professor Fernald compared the insects with figures and
descriptions of the brown-tail moth in the European works,
and at once was able to identify them as the brown-tail moth.
This identification promptly raised the interesting ques-
tion of how these insects had become colonized in the locality
where they were found. To obtain light on this point, care-
ful examination of the infested district was made, and a
8 THE BROWN-TAIL MOTH.
number of owners of infested estates were interviewed. In
this way a large amount of valuable information was obtained,
but, as might be expected, a considerable part of it evidently
pertained to depredations of insects other than the brown-
tail moth. Elhninating these statements, there was still
abundant evidence that the moth had been established in
Somerville for several 3 ears previous to 1897, gradually be-
coming acclimated, and slowly spreading outward into non-
infested territor^^ Many of these statements from owners
of infested propert}^ were of especial interest, and it is well
to record several of the more important at this point.
Mr. W. I. Chase, living at 85 Vine Street, Somerville,
Mass., stated that he moved tt) his present place in 1892.
In the spring of that year the caterpillars of the brown-tail
moth defoliated a few pear trees, and then, driven by want
of food, descended to the ground and attacked rhubarb and
other plants, greatly injuring his garden crops. Since that
date the caterpillars were more or less abundant each year,
and in May, 1897, had stripped nearly all the fruit and shade
trees on his place. ]Mrs. Chase stated that in the smiimer
of 1890 the house and buildings adjacent "fairly swarmed
with white moths."
Mr. J. A. Merrifield, 48G Somerville Avenue, Somenalle,
Mass., had noticed the webs of the brown-tail moth on his
pear trees for at least three years preceding 1897, and up to
that year had cut off and destroyed the webs each winter,
thus applying of his own initiative the best remedy for pre-
venting damage by the moth. As a result of this treatment,
his trees were preserved from damage, while those of his
neighbors were more or less defoliated. Owing to other
duties in 1897, this work of web destruction was neglected
until Patriot's Day, April 19, when they were destroyed as
usual. This date proved too late, as the caterpillars had
emerged and were crawling over the trees in great numbers,
and as a result many of the trees were defoliated. Mr. Mer-
rifield stated that he examined several webs April 1, and
found that they contained masses of caterpillars, hence
thought it safe to delay treatment until the holiday men-
tioned. Particular interest attaches to Mr. Merrifield's state-
THE BROWN-TAIL MOTH. 9
ment, as he is a conservative man, and possesses a good
general Icnowledge of our common insect pests.
Mr. H. Foster, 23 Park Street, Somerville, Mass., removed
and burned the tents on his trees eacli spring from 1895 to
1897. This was done before the caterpillars left the webs,
and as a result his trees retained their foliage, while those
of his neighbors were almost entirely defoliated.
Mr. John Walker, living at 2 Arnold Court, Somerville,
Mass., stated that for more than three years previous to
1897 he had noticed damage by these caterpillars, the num-
ber of the insects increasing each year.
These statements indicate that the moth had been suffi-
ciently numerous to cause noticeable injury since 1892-94.
It is entirely probable that it occurred in small numbers for
several years before it Avas noticed by property owners, so
that it is safe to set the date of its introduction tentatively
at about 1890. The question has been raised why the moth
was not discovered at an early date by the employees of the
gypsy moth committee. This is explained by the fact that
in the part of Somerville where the moth was found the
gypsy moth force had not worked for several years. Fur-
ther than that, these men were obliged by law to confine
their work to the gypsy moth, hence did not pay special
attention to other insects unless they became injuriously
abundant.
Introduction of the Moth.
It seemed entirely probable that the place of the original
introduction of the moth would be found in the worst-infested
locality, as the insects would naturally increase in numbers
and spread outward from year to year. An examination of
the territory showed that the area of greatest damage was
near the Somerville depot on theFitchburg Railroad. Here
by the middle of June the devastation had become truly
formidable. Pear and apple trees were entirely defoliated,
shade trees suffered severely, while even shrubs and herbage
were not exempt from the attacks of the ravenous insects.
Travelling outward in any direction from this point as a
centre the damage by the moth gradually grew less, until
at a distance of between one and two miles the infestations
10 THE BROWN-TAIL MOTH.
of the moth were merely sporadic and localized. Within
the badly infested area there were two establishments which,
from an entomological stand-point, were of a highly suspi-
cious character, viz., an old abandoned nursery and a large
greenhouse and florist's plant.
Realizing how easily the insects in theu: closely spun webs
might have been imported on nursery stock, the old nursery
was carefully examined and the history of importations there
made was investigated. It appeared that the nursery had
not been in active operation since about 1895, and many of
the trees left standing in the old nursery rows had attained
to a large size. Among the latter there were several large
specimens of Pp-us, a genus particularly favored by the
caterpillar. Had the insect been introduced here, the nurs-
er}^ with its surrounding yards, containing numerous fruit
trees of considerable age, would have offered ideal con-
ditions for the multiplication of the moth, and here we
would have found ample evidence of long-continued infesta-
tion. On the contrary, however, careful examination of the
nursery and the surrounding estates showed less than a dozen
trees infested by the caterpillars.
Owing to the unpopularity of the moth, questions tending
to connect any one with its importation were necessarily
made in a guarded manner. The second suspicious place,
the florist's establishment, perhaps one-fourth of a mile
from the nursery, was visited, and the proprietors were
questioned indirectly with reference to their importations
of foreign perennials or shrubs. It was found that previous
to about 1890 these parties had made a feature of importing
roses from Holland and France, growing them for a year or
two in large plots in the rear of the greenhouses, and then
marketing them. Immediately in the rear of these plots
were two blocks of large, full-grown pear trees, and these
trees were completely defoliated by the caterpillars, and had
a history of repeated defoliations extending backward for
tlu-ee or four years. Now, it is well known that the brown-
tail moth occurs both in Holland and France ; that in these
countries it is not an uncommon pest of roses, — in fact, it
is frequently mentioned in literature as being one of the
Plate 2.
Large web of brown-tail moth on apple. This web was made by the
consolidation of several colonies and contained
2218 small caterpillars.
I
THE BROWN-TAIL MOTH. 11
important pests of roses. We know that it spins its winter
webs freely on the rose, and that rose bushes are ahvajs
imported in the fall, winter or spring, while both the bushes
and the insects are in a dormant condition. The fact that
this oreenhouse was in the centre of the worst moth-infested
district, and in consideration of the facts previously enumer-
ated, makes the circumstantial evidence strong that the
brown-tail moth was brought to this locality accidentally
on imported roses, escaped, and spread naturally through-
out the district. This case is but another excellent illustra-
tion of how the agencies of commerce and the business
intercourse l)etween nations are fast bringing about a world-
wide distribution of our principal insect pests.
"It is indeed a strange fatality that another European-
insect, closely related to the gypsy moth by habit and
structure, should become accidentally imported to the same
locality to which thirty years before a misguided scientist
brought the gypsy moth. It would seem that the world is
large enough to give each of these pests a separate ' sphere
of influence.' That they were both transported across the
Atlantic to the same locality by totally dissimilar agencies
must stand as one of the remarkable entomological events
of the century just closed." * Now that we know the
habits of the caterpillars in spuming their webs on so many
different slu'ubs and trees valued for their fruit or for orna-
mental purposes, it seems all the more remarkable that the
insect was not imported years ago. Our long immunity
from the pest is greatly to the credit of European nursery-
men, and gives evidence of the care with which nursery
stock is selected and prepared for export. There is of
course danger that the moth may be accidentally dissemi-
nated in this country by jNIassachusetts nurserymen, — a
danger which we believe they will carefully guard against,
as they have been fully advised concerning the matter by
our efficient State Nursery Inspector, Dr. H. T. Fernald.
* Kirkland, Report Massachusetts Horticultural Society, 1902.
12 THE BROWN-TAIL MOTH.
The Brown-tail Moth in Europe.
The original home of the brown-tail moth is in Em^opo,
where it octairs over the entu'C country except in the extreme
north. Altum (juoti?s Speyer to the effect that it is "dis-
tributed over the whole of central and southern Em-ope,
extends into Algiers on the south and to the Himalayas on
the east. The polar limit is in Sweden at 57°, the equato-
rial in the Himalajas at 34°." Kirby states that it is "com-
mon in central and southern Em'ope, north Africa and western
Asia, but is a local insect in Enoland." The moth has
also been doubtfully reported from Japan. This wide dis-
tribution is significant, as indicating the ultimate probable
range of the insect in the United States.
The literatm*e of the brown-tail moth is as old as the lit-
erature of economic entomoloijv. When man be^an to record
his troubles with the pests of crops, this insect was among
the first to receive attention. The remarkable outbreaks of
the caterpillars in certain years created astonishment as well
as alarm. Being clearly out of the established, order of
things, they were regarded as a punishment for human short-
comings ; and as Divine interposition seemed to ofler the
only remed}^ it. was freely invoked to stay the plague.
Thus in 1543, diu-ing an outbreak of the brown-tail moth,
a member of the city council at Grenoble introduced a re-
solve besfging the local church official "to excommunicate
these pests and censure them, in order to check the damage
they were doing daily." To the credit of the council, let it
be added, the resolve was promptly enacted. In the same
century, Chorier, a historian of Dauphin}^, relates that these
caterpillars were so abundant that the attorney-general of the
province found it necessary to issue an injunction against
them, and ordered them to evacuate the fields where they
were feeding. Such records as these testify strongly to the
early damage by the moth, and the helplessness of the farm-
ers of that day in the face of the caterpillar outbreaks.
Goedart, writing in 1635, describes the " singular nature "
and " remarkable knowledge and foresight" of the caterpil-
lars in preparing their winter shelters. Madam Merian de-
THE BROWN-TAIL MOTH. 13
scribed the habits of the moth in 1683, and Albin in 1720.
In 1731, Reaumur, travelling from Tours to Paris, "found
every oak in possession " of these caterpillars, and later
made very complete studies of their liabits. Roesel, in 1746,
mentions and describes the moth. Linnaeus described tlie
moth in his " Systema Naturae," Vol. I., p. 502, 1758, and
gave it the scientific name Bombyx chrysoi'rhoea. The genus
Bomhyx of LinnaBus has been divided by later entomologists
into a large number of genera, based on structural charac-
ters ; and this species, forming the type of tlie new genus
Eui^roctis^ is now known by the scientific name of E^qwoctis
chrysorrhoea (L.). Since the time of Linnaeus the brown-
tail moth has been figured and described by nearly every en-
tomologist who has written on the moths of Europe, and
more or less complete accounts have been given of its life
history and habits.
Geoffro}^ in his "Histoire abregee des Insectes," Vol. II.,
p. 117, 1762, in writing of the broAvn-tail moth in the
vicinity of Paris, says that it is the most conmion of all
caterpillars, and is found on almost all trees, which it
often entirely defoliates in the spring.
In 1782, William Curtis published an account of the dep-
redations of the brown-tail moth, in which he informs us
that at that time " the inhabitants of London and its vicinity
were thrown into the utmost consternation " at the hosts of
caterpillars of this species, that completely stripped the trees
and shrubs of their leaves for miles in many j)laces. The
general a})})earance was such as might well cause alarm ; for
plants, hedges and " whole plantations of fruit trees, as well
as trees of the forest, shared in the general havoc, presenting
their leafless branches in the midst of summer as though
stricken and destroyed by the blasts of winter. An appear-
ance so extraordinary was calculated to create terror ; it was
naturally interpreted as a visitation from heaven, ordained
to destroy all the soiu-ces of vegetable life, to deprive man and
cattle of their essential food, and finally leave them a prey
to famine" (Donovan). The alarm of the public was so
great and prevailed to such an extent that prayers were
publicly offered in the churches to avert the calamity. Be-
14 THE BROWN-TAIL MOTH.
lieving, doubtless, that in emergencies works are as neces-
sary as faith, the town fathers oflered a shilling per bushel
for the caterpillar webs. These latter were cut off and
burned "under the inspection of the church wardens, over-
seers or beadle of the parish ; at the first onset of this busi-
ness, four score bushels, as I am credibly informed, were
collected in one daj', in the parish of Clapham " (Curtis).
Olivier, in 1790, mentions the insect as very common in
the neighborhood of Paris, where it feeds < ' indifferently on
all fruit trees and on nearly all other trees ; one finds them
as frequently in the forests as in the hardens."
Writing in 1803, Ha worth, "Lcpidoptera Britannica," p.
109, states that "the caterpillars of this insect have some-
times become so exceedingly numerous as to do incredible
damage to the vegetable kingdom," and refers to the historic
outbreak at London in 1782. Donovan, in his "British
Insects," Vol. XVL, pp. 39-45, 1813, gives a good general
account of the habits and damage by the insect, and quotes
freely from Curtis's pamphlet on the moth, — a work that has
now become very rare. Bechstein, in " Forst u. Jagdw.,"
4th, 2 Bd, 1818, describes the moth under the name of "white
thorn sj^inner," from its habit of attacking this shrub. He
writes: " It is said that these caterpillars have devastated
whole areas of forest, particularl}^ oak wood lands. They
are most injurious in the fruit garden." He notes that the
caterpillars "in the spring gnaw the buds, blossoms and
leaves, and strip even the second crop of leaves from the
tree. The}- also destroy the fruit, and make the tree sickly
through sap exhaustion."
J. B. Godart, "Hist. Nat. des Lepidopteres," Vol. 4, p.
273, 1822, comments on the law which required French
property owners to clear their trees of the winter webs,
and expresses the belief that a better plan would be "to
destroy the clusters of eggs immediately after they are laid, "
— a method which is of course wholly impracticable where
large trees arc infested. Blumenbach, 1825, considered this
insect " one of the most destructive caterpillars to fruit trees ; "
while four years later, M. Wani. I used to pour
kerosene on them, and then take a pan and brush them off my
plants and off the house. Sometimes ] would get two or three
quarts of the w^orms. They were a sight. Vou could not get out-
side the door without being poisoned by them. AVhile the leaves
on the trees lasted, the}^ let the plants alone ; but when they were
gone, they ate my rose bushes and other shrubs. We had no
fruit at all in 1897. There must have been some of them here
previous to that time, for I remember seeing the nests on my
neighbor's trees, and telling him if he did not cut them off he
would have no fruit, little thinking at the time that my own trees
would be eaten up. We had to cut two apple trees down, be-
cause they were so covered with the nests. The insects have not
bothered us as much this summer, 'I'lie work we did last spring
kept them from being so numerous.
Mrs. M. jNIcCarthy, 8(S Beacon Street, Somerville, writing
in October, 1898, says: —
We found the brown-tail moths a terrible nuisance, because they
spoiled our fruit. We used to have a great deal of nice fruit from
our trees, but since the moths came the little fruit we have had
has been very poor. In 1897 we had one tree that was just full
of fruit, and it was destroyed by the caterpillars. In years past
we used to get from ten to twelve bushels of pears, and this year
we had only two bushels. One of our apple trees that has some-
times given us two barrels of apples this year yielded only about
half a peck. The caterpillars were very much worse this year than
the year before. This year in the early spring we could not go
into our j'ard because of the caterpillars. I hired a man twice to
come here and cut the limbs oft' the trees, once in the spring and
again later ; but in spite of all our efforts we could not keep them
down.
The swarming of the caterpillars actually injured the value
of real estate in the worst-infested districts, since tenants
THE BROWN-TAIL MOTH. 23 ,
would not lease property so located, while those occupying
houses near which the caterpillars were abundant often were
forced to vacate the same. Mr. L. L. Tower, of the Tower-
Cutter Company, Boston, writes us : —
The year before the browu-tailed moth appeared in my pear
orchard at SomerviUe it produced over two hundred bushels of
pears ; the next year the caterpillars were on the trees by the
bushel, and I did not have a pear that or the following year.
The damage by the caterpillars was a great annoj^ance, not only
to my tenants but to the neighbors. As a consequence, my ten-
ants moved out and left the house vacant for about a year.
Mrs. E. Gibson, 72 Beacon Street, SomerviUe, says: —
We were all badly poisoned by these moths. We did not know
that they were here when we took the house, and so we have had
to bear the consequences. My husband spoke to the owner of
these premises, and told him that unless something was done we
could not stay. He said he knew they were dreadful things to
have around, but did not seem to be able to do anything. The
trees were eaten up by them, and we had no fruit whatever.
They troubled us more or less all summer. They seemed to be
worse here than anywhere, but all our neighbors were troubled
with them and tried to get rid of them. The trees and grass were
covered with them. We used to take brooms and try to sweep
them off the piazza, and we had to guard against their getting
into the house. They were a regular plague.
Mrs. Alexander Garboti, 160 Park Street, SomerviUe,
says : —
The first time these caterpillars troubled us was in 1897, and
then they were terrible. Everyone about here complained of them.
They were not only outside but inside the house. I found them
on my pillows. One of my tenants moved away on account of
them. My tenant who lived up stairs could not open her windows.
The caterpillars were all over her piazza, and she could not sit
there because of them. She would brush the caterpillars up with
the broom into a good pile, and then call me to look at them ; and
I would have to hold the pan while she swept them up, and then
we carried them to the back yard and burned them. This was
very bad for me, and poisoned me dreadfully. My neck was all
swollen up and red with a rash.
24 THE BROAVN-TAIL MOTH.
The testimony of such witnesses gives unquestioned evi-
dence of the damage caused by the moth. A large number
of statements equally interesting and of the same general
tenor have been omitted, as being only corroboratory.
Public interest in the moth was most intense wherever the
insect had appeared in force ; trees were devastated, garden
crops destroj'cd, and dwellings swarmed Avith the caterpil-
lars ; while to the gyps}' moth committee and their em-
ployees went forth in no uncertain tones the IMacedonian
cry, "Come over and help us," — an appeal to which the
conmiittec did not turn a deaf ear.
The 1897 outbreak was novel and even alarming, hence
property owners observed the caterpillars more closely than
in later years ; yet each year since in sections where the
moth has been neglected the same devastation of trees, the
same migrating of hungry caterpillars, the same injury to
human beings, has occurred. AVherever -web destruction
at the proper time has been properly carried out, either by
individuals or municipalities, a notable degree of freedom
from damage by this insect has been secured.
The Campaign auainst the Moth.
As soon as the identity of the brown-tail moth had been
settled, the infested district was thoroughly examined by
Messrs. Fernald and Kirkland, accompanied by President H.
H. Goodell of the Hutch Experiment Station of the Massa-
chusetts Agricultural College. Appreciating the gravity of
the situation. President Goodell authorized the preparation
of a special bulletin on the insect, which was published by
the Hatch Experiment Station in July, 1897, and generall}'-
distributed in the metropolitan district. The presence of
the moth was also brousfht to the attention of His Excel-
lency the late Governor Roger Wolcott, by the following
letter from the gypsy moth committee and the director of
the Experiment Station : —
Boston, May 25, 1897,
His Excellency Roger Wolcott, Governor of the Commonwealth.
Sir : — We desire to submit for your consideration the facts
relative to another insect pest which has appeared for the first time
iu this Commonwealth and in the United States.
r'late 5.
Pear tree stripped by brown-tail moth caterpillars,
Medford, Mass , May 17, 1899.
THE BROWN-TAIL MOTH. 25
It is commonly called the brown-tail moth {Euproctis chrysor-
rhoea), and is so destructive in its habits, having so wide a range
of food, that in European countries it is one of the few insects for
the suppression of which laws have been enacted.
The centre of the infested district in this State appears to be in
Somerville, though how widely the insect is dispersed we have been
unable to determine in the short time intervening since its appear-
ance. In an examination of the district by our entomologist,
Prof. C. H. Fernald, and Dr. L. O, Howai-d, chief of the Division
of Entomology, Department of Agriculture, Washington, D. C,
the insect was found feeding on the pear, apple, cherry, straw-
berry, raspberry and rose bushes. The trees were entirely stripped
of their leaves, and the trunks, fences and sidewalks were swarm-
ing with the caterpillars.
The side of a house in the vicinity was covered with them, and
they had even pushed their way into the interior. The most seri-
ously affected point is immediately around the depot and railway
tracks, increasing greatly the risk of dispersion.
The caterpillars are just finishing their feeding state, and will
soon go into the pupa condition. The time to attack them is now,
by contact insecticides, and in the late summer when they emerge.
Dr. Howard, government entomologist, now here inspecting our
work on the gypsy moth, has kindly consented to give the benefit
of his advice.
To meet this sudden emergency, a special appropriation of
$10,000 from the Legislature seems absolutely necessary', and we
therefore beg Your Excellency to take such steps as seem in your
judgment best.
E. W. Wood,
Augustus Pkatt,
S. S. Stetson,
John G. Avery,
F. W. Sargent,
Wm. R. Sessions,
Committee of the Board of Agficnlture
on Oyiisy Moth, Insects and Birds.
Henry H. Goodell,
Director Hatch Experiment Station.
The matter was also presented to the Governor orally by
the gypsy moth committee, Messrs. Fernald and Kirkland,
with Dr. L. O. Howard, entomologist of the United States
Department of Agriculture, who fortunately was in Boston at
26 THE BROWX-TAIL MOTH.
that time. On May 27 it was brought to the attention of
the Legislature by special message from Go\'ernor Wolcott.
The matter was referred to the auricultural committee, and
on June 3 that committee, through Representative W. H.
Porter of Agawam, reported a bill })lacing the work of de-
stroying the brown-tail moth in the hands of the gypsy
moth committee, and appropriating $6,000 for the needs
of the work. On June 8 the ways and means committee
reported adversely on the bill. Later in the session a bill
presented by Col. Albert Clarke of Wellesley, and requiring
local authorities to suppress the moth, was passed to be en-
acted, and is presented in full below^ : —
[Chapter 516, Acts of 1897.]
An Act to require local authorities to suppress the brown
TAIL moth.
Be it enacted, etc., as follows :
Section 1. Whenever the pest known as the brown tail moth
shall be discovered in any city or town of th^ Commonwealth it
shall be the duty of the city or town government to take imme-
diate steps for its extinction and to prevent its spread. If they
are in doubt what the pest is, they shall notify the board of agri-
culture, and whenever they are informed by said board that such
pest exists within their respective municipalities they shall at once
enter upon the work of its confinement to the infested area and its
suppression.
Section 2. It shall be the duty of the board of agriculture to
cause inspections to be made upon the receipt of notice from local
authorities, and also whenever the board has reason to suspect
the presence of this pest in any city or town, and to furnish the
local authorities an ample supply of printed directions as to the
best methods for its confinement and extinction.
Section 3. It shall be the duty of the owners and managers of
premises infested by this moth to exert themselves persistently to
confine and suppress it, under the direction of local and state
authorities, and to promptly report any spread of the pest which
they may discover.
Section 4. Mayors and aldermen of cities and selectmen of
towns who shall neglect or refuse to comply with the requirements
of this act shall, on information or complaint of the district attor-
ney or on indictment by the grand jury, and on conviction of such
neglect or refusal, be fined ten dollars each for every day of
THE BROWN-TAIL MOTH.
27
such neglect or refusal after the receipt of due notice from the
board of agriculture that their city or town is thus infested.
Section 5. The owner or manager of any infested premises
who shall, after the receipt of a notice in writing from the mayor
and aldermen of his city or from the selectmen of his town, or
from the board of agriculture, neglect or refuse to comply with
this act, shall upon conviction of such neglect or refusal, before
any court of competent jurisdiction, be fined one dollar for every
day of such neglect, or confined in. jail not more than five days
nor less than one day, or suffer both penalties in the discretion of
the court.
Section 6. This act shall take effect upon its passage. \^Ap-
proved June 11, 1897.
In the mean time, the caterpillars were swarming in large
numbers along the line of the Fitchburg Railroad at Somer-
ville, and were evidently being scattered on trains. A few
of the employees of the gypsy moth committee therefore
were detailed to stamp out this pest spot, and this was done,
the caterpillars being destroyed by spraying with soap solu-
tions and kerosene emulsion. On June 24, 1897, the ex-
ecutive conmiittee of the Board of Agriculture voted to
advise the mayors of Somerville, Cambridge, Maiden, Med-
ford and Everett that the brown-tail moth had become
colonized in their respective municipalities, and urging
them to take means to secure its suppression. It was also
voted to spend a sum not to exceed $150 in examining
towns thought to be infested. As a result, it was found
that the moth had already become widely dispersed. The
result of the examination made in the fall of 1897 is given
below : —
Somerville,
Cambridge,
Medford,
Maiden,
Everett,
Melrose,
Stoneham, . . .
Arlington, .
It is probable the moth was distributed elsewhere at the
time of this inspection, which from lack of funds was neces-
ifested
Estates.
1,411
Winchester,
21
355
Woburn,
19
149
Charlestown,
7
92
Belmont,
3
72
Burlington,
3
31
Saugus,
2
31
Revere,
1
29
28 THE BROWN-TAIL MOTH.
sarily a limited one. More or less activity was shown on
the part of municipalities in suppressing the moth in the
winter of 1897-98, particularl}^ in stamping out the worst-
infested spots in Somerville and Cambridge. June 20, 1898,
the law relative to the brown-tail moth was amended, and
the following law enacted : —
[Chapter 5i4, Acts of 1898.]
An Act to require the state board of agriculture to take
charge of the work of exterminating the brown tail
MOTII.
Be it e7iacted, etc., a.<! follows :
Section 1. AVlienever the pest known as the brown tail moth
is discovered in any city or town of this Commonwealth, it shall
be the diitv of the state board of ao;rieulture to take immediate
steps to prevent its spread ; and, in the discharge of the duty im-
posed upon said board In' this act, said board is hereby vested
with all the powers now conferred upon it by law in exterminating
the gypsy moth, and may expend of the money heretofore appro-
priated for the extermination of the gypsy moth a sum not exceed-
ing ten thousand dollars.
Section 2. Any person who purposely resists or obstructs said
state board of agriculture or any person or persons in its employ,
while engaged in the execution of the purposes of this act shall
be punished by a fine not exceeding twentj'-five dollars for each
offence.
Section 3. It shall be unlawful for any person knowingly to
bring the insect known as the brown tail moth, or its nests or eggs
into this Commonwealth, or for any person knowingly to transport
said insect or its nests or eggs from any town or city to another
town or city within this Commonwealth, except while engaged in
and for the purposes of destroying them. Any person who vio-
lates the provisions of this section shall be punished by a fine not
exceeding two hundred dollars or by imprisonment in the house
of correction not exceeding sixty daj^s, or by both said fine and
imprisonment.
Section 4. Chapter five hundred and sixteen of the acts of the
year eighteen hundred and ninety-seven is hereby repealed. [_Ap-
proved June 20, 1898-
This brought the work of suppressing the moth directly
under the control of the gypsy moth committee. It was
decided to delay active measures until the fall, when a
THE BROAVN-TAIL MOTH. 29
campai""n of web destruction was commenced, in which
laro-e masses of webs, particularly in Cambridge, Somer-
ville, Maiden, Medford and Everett, were destroyed, the
sum of $9,998.96 being spent in this work. Up to Jan. 1,
1899, thirty-two cities and towns were found infested by
the moth.
Work against the brown-tail moth was continued by leg-
islative enactment with another appropriation of $10,000,
deducted from the sum appropriated for work against the
o-yp.sy moth. This was chiefly spent in web destruction
late in the fall, the actual sum ex})ended in this work being
$9,999.81.
During the year 1899 the following work was accom-
plished : —
Trees inspected, 413,758
Trees sprayed, . • • • • • • 2,517
Old winter webs destroyed, 13,519
New winter webs destroyed, 884,480
With the cessation of the State work against the gypsy
moth and brown-tail moth, in February, 1900, it became
necessary for municipalities to enter upon a campaign against
the latter insect.
This work was taken up in good si)irit by the worst-in-
fested municipalities, and has been carried out to a greater
or less extent each winter since that time. Cambridge, Som-
erville, Medford and Lynn have been particularly active in
destroying- the broAvn-tail moth, and as a result these cities
have been quite generally exempt from damage by these
caterpillars in the summer season. These operations have
been largely directed toward the destruction of the moth
on street trees. Many cities have taken the broad — and it
seems to the writers entirely correct — view that the moth
on private estates, if neglected, is a menace to the shade
trees of the city as well as to the property of other citizens.
Where this view has been held, the moth has been destroyed
on street trees and private trees alike ; and, as a result of
this treatment, cities like Someryille and Cambridge have
gained quite a degree of immunity from the insect. Unfor-
tunately, however, where certain cities light the moth in a
30 THE BROWN-TAIL MOTH.
thorough and intelligent manner, adjoining municipalities
sometimes neglect the moth entirely, or combat it only
in a half-hearted manner. This has resulted in undoinir each
year a large part of the good Avork accomplished in localities
previously freed from the moth. This state of affairs gives
an additional reason for the necessit}^ of thorough sys-
tematic Avork over the entire district, if the moth is to be
suppressed.
Painful Nettling from the Caterpillars.
Coincident with the swarming of the caterpillars along
fences, Avalks and on house walls, a very painful cutaneous
eruption developed among citizens of the worst-infested dis-
tricts. This affection developed usually on the hands, face
or neck, spread rapidly, and produced an intolerable itching.
At first the cause of the trouble was not recognized b}' the
local physicians, and some anxiety was felt, at least on the
part of the sufferers, lest a new epidemic disease had made
its appearance. It was soon traced, however, to its proper
source, — the hairs of the brown-tail moth caterpillar. This
feature of an insect outbreak is so unusual in America that
it is worthy of particular mention. Briefly stated, it was
found that whenever the living caterpillars, or even the
cast-off caterpillar skins formed in molting or spinning the
cocoons, came in contact with the human flesh, the eruption
followed as a natural but painful seijuence.
This nettling of the human skin by caterpillars is not an
unusual occurrence, but insects causinij it, other than the
brown-tail moth, are fortunately rare. One of our large
caterpillars, not uncommon on ash and apple, the larva of
the lo moth (Autoineris to), is armed with spines that poison
the skin ; while the same holds true with the southern sad-
dleback caterpillar (^Empretia stimulea). The injur}^ in
these cases is comparable to the stinging of bees or wasps,
a poisonous substance gaining entrance beneath the skin.
Common illustrations of nettling from caterpillar hairs are
found in the case of the hickory caterpillar (Hahsidota
caryce) or the white-marked tussock moth (JSTotolophus leu-
costigma) , The injury from the hairs of these insects is not
THE BROWN-TAIL MOTH. 31
to be compared in point of severity with tliat caused by the
hairs of the brown-tail moth caterpillar, which is of a pecul-
iarly intense, burning character. So far as known to us,
no American insect can compare with it in this respect, al-
though it is probably exceeded in severity by the urtication
caused by the processionary caterpillar of Europe ( Thau-
metopoea processtojiea) .
In orchards where there are large numbers of brown-tail
moth cocoons, a liaht breeze is sufficient to waft the irritat-
ing hairs upon passersby, with most annoying and painful
results. In investigating the habits of these caterpillars in
the field we were often severely nettled by the hairs, and
can testify that the intense irritation lasts for several weeks.
The principal sufferers from this feature of the caterpillar
outbreaks are women or children, who by necessity or habit
are often confined quite closely to badly infested estates.
Among these parties the suffering frequently beggared de-
scription.
Statements from Sufferers.
Mrs. H. F. Williams, 213 Beacon Street, Somerville,
says : —
We were shockingly poisoned by the caterpillars of the brown-
tail moth. They troubled us all summer. Every member of my
family was poisoned. At first we did not know what they were.
My little boy could not go near them without getting poisoned ;
every time he went to pick cherries he would come down from the
tree badly poisoned. If my baby went near where they were, his
face would break out into a rash. I was so dreadfully poisoned
that I thought I had some frightful disease. My hands, face, neck,
arms and limbs were broken out with this rash. Most of the cat-
erpillars we had in 1898 came from a neighbor's place. They came
over the fence, into the house and even into the closets. They
would get on clothes hung on the line, and when these were worn
they poisoned us.
Mrs. E. L. Bailey, 21 Medford Street, Maiden, writes : —
I was badly poisoned on my neck and arms by the caterpillars.
At times I was nearly crazy with the itching and irritation caused
by the poison, and one of my children was affected in the same
way.
32 THP: BKOWN-TAIL MOTH.
Mr. Da'^iiel E. Chase, a well-known Sonierville citizen,
has written us : —
My whole family suffered from poisoning by these creatures,
the skin being so badly irritated that we were obliged to bathe in
soda water, salt water, etc. We felt the effects of the poisoning
all summer. When my house was painted, the painters, in scrap-
ing under the eaves, started up the hairs of the caterpillars, and
we were thus all more or less poisoned again.
Mrs, .1. Lcland, o77 AV'ashington Street, Sonierville,
says : —
The caterpillars are very dangerous, because the}' are so poison-
ous. They seem to poison everything they touch. We had to
wash all vegetables brought in from the garden. My son, who
worked in the garden a great deal, was badly poisoned ; his neck
was a solid mass of rash. The rest of the family were also
poisoned in a less degree.
Miss McMahon, living- at (582 Somerville Avenue, Somer-
ville, says : —
We first noticed the caterpillars in 1897. They were all over
the trees. At the same time we began to have a dreadful itching,
from which we suffered so nuich that we were obliged to consult a
physician.
A Typical Experience.
A typical experience with the caterpillars is described
by Mrs. C. D, Chase, living at 18 Ivaloo Street, Somer-
ville : —
While cutting the limbs from the infested trees my husband was
badly poisoned, his eyes in particular being affected. In cleaning
the window screens in the house I was also badly poisoned ; the
skin of my body was as much inflamed as if a mustard paste had
been applied. The poisoning did not seem to come entirely from
contact, but the air seemed to be filled with something which
caused the itching and burning sensation. We were affected dur-
ing the whole two months that the insect was in the larval stage.
In 1897, while the house was being painted, the painters all suf-
fered more or less. Their distress was so great that they were
obliged to stop their work and bathe the face, hands and arms
with soda water to get relief. We could not hang out the clothes,
as the hairs would cling to them, especially to the flannels, and
when worn they would badly irritate the skin.
Plate 6.
Fig. 1.
Fig. 3.
Fig. 2.
■ "I'lm'
Fig. 5
Explanation of Plate
Figures Nos. 1, 2, 4 and 5 drawn from nature by J. H. Emerton
No. 1. — Female brown-tail moth.
No. 2. — Winter web of brown-tail moth caterpillars.
No 3. — Pruning shears suitable for removal of winter webs.
No. 4 — Brown-tail moth caterpillars, enlarged.
No. 5. — Brown-tail moth caterpillars, natural size.
THE BROWX-TAIL MOTH. 33
Mrs. J. A. Chabot, 15 Park Street, Somerville, states : —
"We were all badly poisoned by the caterpillai-s. We could not
go into the yard without getting the irritation on the neck and
arms, although we covered ourselves up as well as we could, in
order to escape them. The man who took care of the yard was
badly poisoned. Only a few caterpillars got into the house, but I
suppose they came in on our clothing. This spring, when putting
the screens on the windows, I noticed some of the cocoons on the
clapboards, and scraped them off- As a result, my neck became
badly poisoned.
Nicholas Fleming, corner of Kent and Beacon streets,
Somerville, says : —
The poisoning by the caterpillars was truly dreadful. Every
time we went into the yard we had to protect ourselves about the
neck and head, to keep them off.
Mr. C. E. Kenniston, 17 Park Street, Somerville, writes : —
Both myself and family were greatly troubled by the sting or
bite of these caterpillars. It seemed as if they poisoned us when-
ever we went near one of them. The webs made by the insects
seemed to be poisonous. We had an awful time with them, and
my son's face and hands were so badly puffed up that he had to
call in a doctor.
Mrs. W. I. Chase, 85 Vine Street, Somerville, a most in-
telligent observer of the habits of the moth, states : —
In 1897 the caterpillars poisoned us terribly, and even now,
when we go out and sweep down the sides of the house where the
cocoons are, we get poisoned in the same way. While putting a
new roof on the house my husband was nearly wild from the pain,
and my neighboi's tell me that every time they wash their windows
they are poisoned.
Mrs. J. A. Kincaid, 88 Vine Street, Somerville, says : —
Our whole family was badly poisoned by the cater[)illars. It
took us all summer to get rid of the poison. Even now (October,
1898), when we get overheated the poison breaks out again on
our bodies. One of my neighbors was so unfortunate as to get
poisoned in one of her eyes, and had a hard time.
34 THE BROWN-TAIL MOTH.
Miss West of 42 Preston Street, Somerville, on returning
home from an absence of several weeks,
was badly poisoned by the caterpillars. I had not been home
twenty-four hours before I was poisoned. I did not know that
the insects had gotten on me, and at first thought I had the
measles. The trouble lasted for several weeks, and then gradually
wore away.
Henry Foster, 23 Park Street, Somerville, says : —
The caterpillars did not poison us until they got very thick. I
suffered badly with them ; I could not get rid of them, and chang-
ing my clothing seemed to do no good. Our neighbors were
troubled more than we were. One of them was so ill that she had
to call a physician.
J. A. Merrifield, previously quoted, states: —
In 1897 we were much bothered by the poisoning of the cater-
pillars. You could not sit under the trees ten minutes before you
would begin to feel the itching sensation. You might not find a
caterpillar on you anywhere, but it would be only a few minutes
before you would begin to itch.
'Mrs. J. O'Connell, 82 Beacon Street, Somerville, says : —
This summer whenever we sat under the trees we would have a
terrible itching. The caterpillars poisoned me very badly. My
hands, arms and face were covered with rash, and my children
were broken out in the same way.
A Severe Case of Poisoning.
From the nature of his work, Granville A. Walker, 9
Loring Street, Somerville, became badly poisoned by the in-
sect, his case being one of the most severe in the devastated
district. It is of particular interest, since the nettling came
not from the caterpillars, but from the cocoons spun on
house walls. He has written us : —
I was painting a house on Vine Street in July, 1897. There
were some caterpillars on the trees and- many webs containing
cocoons. Some of the branches were so near the house we were
obliged to cut them off. The house was covered with cocoons
also ; we found them under the clapboards, and of course had to
THE BROWN-TAIL MOTH. 35
brush them off. Mj wrists aud arms were poisoned, and soon
became a sight. Some of my men were also badly affected, and
all of them were more or less poisoned. It was terrible, — simply
terrible ! I had to go to a doctor for relief, and he gave me an
ointment to allay the irritation. A neighbor of mine whose family
had suffered severely from the poison of the brown-tail moth sug-
gested the application of alcohol, as it had relieved her. This
neighbor stated that each week they were freshly poisoned by the
clothes, which, hanging on the line,, came in contact with the hairs
of the caterpillars ; as a result, the skin was irritated when the
clothes were worn.
In my own case, not only were my arms and wrists poisoned, but
my whole body. The alcohol allayed the irritation so that I could
get a little sleep, but the trouble lasted over a month, and was
simply torture, the heat greatly intensifying the suffering. If I
had known about it, I would not have painted the house for
double the price of the job.
A more serious case, no doubt complicated with other
aihiients, has been described to us by Mrs. John H. Mc-
Garr, 80 Vine Street, Somerville, as follows : —
I first noticed the brown-tail moth in May, 1897. My mother
discovered it, and called my attention to it. She saw the little
caterjjillars crawling about, and began killing them ; but the more
she killed, the more numerous they seemed to grow. Soon little
white blisters began to come out upon her neck, and at last, about
the 20th of May, she became very sick, aud we were obliged to
get her away from here, because she was in such a bad state.
The poison seemed to affect her entire body. After she had gone
I became quite sick, also, and could not stay here, but was obliged
to be removed. I was quite weak from the irritation caused by
the eruption. When I scratched the irritated spots, little blisters
would form. The doctor who was called in to attend my mother
said they had poisoned her blood. She grew worse, and finally
died of this poison about the middle of August. The doctor said
her age was against her recovery ; but she was a remarkably well-
preserved woman, and in fairly good health before this occurrence.
My son also was taken quite sick, and finally became so ill that he
also had to be removed from this house. Everything I touched
in the house seemed to be poisoned by the caterpillars. When
the cold weather came I began to get better, but I have never
entirely recovered from the effects of the poison. We had the
36 THE BROWN-TAIL MOTH.
moth again in 1898, but it was not a circumstance to what it
ever had been the previous year. No one who had not seen it
would believe what a scourge it was in 1897. When my hus-
band came home and put on his clean flannels, he said they made
him almost crazy. The caterpillars probably got into them as
they hung on the line. The insects were all over the house, and
the trees were a terrible sight.
Slatements from Physicians.
So severe was the sufiering caused by these insects that
the services of physicians were in frequent demand. State-
ments from doctors living in the infested district and treat-
ing a great many cases of caterpillar "poisoning" are of
particular interest, as giving an accurate summary of the
matter from the medical stand-point. Two well-known
physicians of large experience have kindly given us the
statements which appear below.
George E. Osgood, M.D., 283 Highland Avenue, Som-
erville, writes : —
The past summer (1898) I have had, in round numbers, fifty
cases of what is called dermatitis, or skin disease produced by the
brown-tail moth. Wherever the hair strikes the skin it causes either
small or large blotches. It even goes so far as to produce blebs, an
affection of the skin which varies from a little red spot up to a large
pustule, with pus or matter in it. The first attack lasts about a
week, but one can be poisoned just as many times as the hair
touches the skin. The after-effects seem to be trivial, unless a
person has tuberculosis or dropsy. In a dropsical patient it is
very bad, aggravating the trouble. On Summer Street I had three
cases of poisoning in one family, and on Spring Hill Terrace I had
cases in seven houses. I protected myself from the affection by
using disinfectants after being near the moth. I find that people
with light complexions are affected, apparently, more than those
of dark complexions. By the former it seems to be absorbed by
the system, and the lymphatics are swollen. I do not know of a
case where the lymphatics have been enlarged in a person with
dark complexion. In 1897 there seemed to be less trouble from
poisoning than in 1898. I had but about fifteen cases. We have
had quite a number of the moths about our place this year, although
we had the trees thoroughly cleaned last fall. We have found them
crawling up the trees, making their cocoons in them and under the
eaves of the house.
THE BROWN-TAIL MOTH. 37
Dr. O. A. Gibson, 22 Summer Street, Somerville,
writes : —
The first we saw of these moths was in 1897. The first cases
of poisoning I saw were on Spring Hill Road and Park Street.
I saw a number of cases, and they were all about the same, except
that they varied in point of severity. Some of the cases were very
obstinate, and did not respond well to treatment. The same symp-
toms developed in nearly all cases. The trouble began with an
intense irritation ; then an eruptio-n appeared, resembling eczema,
with a sort of a watery blister on the top. There was intense irri-
tation all over the body, on the head, arms and limbs. I saw
numbers and numbers of cases of this poisoning ; I should say
nearly a hundred cases in all came under my observation. The
irritation seemed to remain, and was much worse than that caused
by poison oak or poison ivy, and was not so easily gotten rid of.
I treated most cases with some cooling application. Some cases
were decidedly obstinate, but no case was serious enough to menace
the life of the patient.
Tlie Cliemistry of it.
A great deal has been written in European works about
the nettling properties of the brown-tail moth, and various
conjectures made as to the cause of the trouble ; but the
general consensus of opinion seems to be that the nettling
is caused by a poisonous substance in or on the finely broken
hairs of the larvse, coming in contact with the skin. Many
also believe the cocoon to be even more troublesome than
the larvffi. In an article in "The Entomologist," Vol. 17,
p. 276, 1884, written from Chichester, Eng., it is stated
that the moths of this species possess this stinging property,
and the opinion is expressed that the irritation is caused by
the white hairs that fringe the inner margins of the wings.
Mr. C. G. Barrett, in his excellent work on the " Lepi-
doptera of the British Islands," Vol. H., p. 294, 1895, writes
as follows : —
With the silk composing the cocoon are interwoven the hairs of
the larva, which becomes brittle, and, when the bush or hedge is
disturbed, are thrown out as a fine dust, which, sticking to the
skin of the hauds, face or neck of a passerby, causes an intense
irritation, with inflammation which closely resembles nettle-rash.
It is on record that a thick hawthorn hedge upon which larvae and
38 THE BROWN-TAIL MOTH.
cocoons have been abundant has retained for months the power of
thus affecting any tender-skinned person rashly assaulting it with
the beating-stick. Mr. H. Moncreaff noticed a larva rubbing its
hairs across the scarlet tubercles on its back, and upon examina-
tion found at the base of each tubercle a valve, opening to a
gland from which an oily substance exuded. This oily substance
he found, on being applied to the skin, to produce at once inflam-
matory swellings, and all the irritation usually caused by contact
with the hairs.
It is well known both to entomologists and to the layman
that certain insects carry specific poisons, which when in-
jected beneath the skin cause acute pain. Bees, wasps,
mosquitoes, bedbugs and other insects fall in this class ; and
chemical investigations have shown that the poisonous prin-
ciples are usually well-defined organic compounds, capable
of being recognized by chemical tests. This being the case,
it was at first supposed that the hairs of the caterpillars con-
tained such a principle, and that the chemist of the gypsy
moth committee, Mr. F. J. Smith, M.S., would soon deter-
mine its nature. A large amount of material, such as
hairs, cocoons and molted skins, was submitted to Mr.
Smith, who extracted them with various solvents with the
following results, which we quote from Mr. Smith's notes : —
I made a number of extracts of the hairs with each of the re-
• agents mentioned below, some of the extracts being of the hairs
alone, others of the molted skins, and still others of the cocoons
which contained hairs in great numbers. The reagents used were :
water, alcohol, ether, chloroform, petroleum ether, acetone, acetic
ether, dilute sulphuric acid, dilute caustic potash. I tested each
of the extracts after digesting for some hours, and in each case
they nettled the skin. On the other hand, the filtered extracts
(freed from the hairs) caused no irritation of any sort when ap-
plied even where the skin was broken. Careful chemical tests
failed to show the presence of any organic acids or alkaloids.
Hence I am led to believe that the irritation is of a mechanical
nature, caused b}' the brittle, finely barbed hairs, and not due to
a toxic principle.
Before submitting the material to Mr. Smith, we had
already discovered that the irritation was not caused by
THE BROWN-TAIL MOTH. 39
the long barbed hairs (Plate 9, Fig. 5) nor by the white
branching hairs (Plate 9, Fig. 1), but by the very minute
barbed hairs which we call the nettling hairs, occurring in
very great numbers on the subdorsal and lateral tubercles
of segments 5 to 12 inclusive (Plate 9, Fig. 3), and also on
the tubercle at the base of the long spines (Fig. 4) , These
nettling hairs are very small, only about one two hundred
and fiftieth of an inch in length, very sharp at one end, and
with two or three barbs at the other end and many along
the sides. These barbs are so arranged that when these
nettling hairs fall upon the skin any movement will cause
them to work into the flesh.
The nettling of the skin may be caused by contact with
the caterpillars in either of the last two molts, the cocoons,
or to some extent with the moths ; but contact is not neces-
sary, as these fine nettling spines may fall or be blown by
the wind. Cases are on record in England of travellers
being afiected when the wind blew strongly from infested
hedges alono- the side of the road.
A careful examination of the caterpillars in each molt
shows that the . nettling spines do not occur except in the
last two stages, or after the row of white spots appear along
each side of the caterpillar. A great quantity of these
nettling spines are always present scattered through the
cocoon and more or less over the surface of the pupa, but in
every case they appeared to have come from the last larval
skin, and never to have developed from the pupae. An
examination of a large number of moths of both sexes
showed many of the nettling spines scattered over the sur-
face of the wings and body in a very irregular manner,
none of which were attached to the integument, but merely
lodged among the hairs and scales of the imago. Only a
few of the nettling spines were found on some specimens,
while on others a laro-e number occurred. In a few cases
many of these spines were found in a confused mass in one
spot, while on another not a single one occurred in that
particular place. We must conclude, therefore, that as the
caterpillar spins its cocoon these spines become scattered
and lodge throughout the fabric, some of them falling on to
40 THE BROWN-TAIL MOTH.
the surface of the pupa after the last molt ; and when the
moth emerges and works its way out through the cocoon,
more of these nettling spines are dislodged from it or from
the molted skin and become entangled among the scales
of the moth. This will explain the unequal distribution of
these spines over the surface of the moths, and the reason
why some possess the nettling properties nmch more than
others. There is nothing in the structure of any of the
scales or hairs on any part of the body or wings of these
moths that could cause them to produce any nettling sensa-
tion.
Fallacies about the Insects.
As might be expected, many false notions prevail con-
corning the manner in which the insects cause the so-called
poisoning. These fallacies are not confined to the average
citizen, for even physicians, arguing from analogy, no doubt,
have fallen occasionally into error on this point. It may
be well to slate, once for all, that the caterpillars do not
sting, since nature has wisely denied them the apparatus
for stinging, as that term is commonly understood ; that
they do not bite, for they have no beak such as is possessed
by the moscjuito or bedbug, while, from the anatomy of their
tiny, blunt jaws, it would be impossible for them to cut
through the human skin ; that they do not eject a baleful
venom, for they have neither the venom nor the means for
ejecting it. Lacking all these attributes dear to the popu-
lar fancy, these insects, with their brittle, barbed hairs ap-
plied in aftectionate contact to the human epidermis, still
possess a means for making one truly long for a place
"where moth and rust doth not corrupt."
Hemech'es.
The injury to the skin being a mechanical one, remedies
must be sought among those materials which soften the skin
and aid in the expulsion of the hairs. Of these, vaseline
and sweet oil are among the best. Alcohol has been used
with success, at least in giving temporary relief, while the
same is true of the numerous coal-tar disinfectants now on
the market. So prevalent is the dermatitis from the cater-
Plate 7.
Typical hair-covered egg masses of brown-tail moth ; laid in July, 1899.
on trees sprayed May 18, 1899, with arsenate of lead. So well
did poison adhere that caterpillars died as fast as hatched.
Photo, Maiden. Mass., Sept. 30, 1899.
THE BROWN-TAIL MOTH. 41
pillars in the metropolitan district in the summer months
that druggists put out special lotions for the " broAvn-tail
moth itch," many of which are meritorious.
Life History.
The moths emerge from the cocoons from the 1st to the
20th of July, and fly principally by night. In marked con-
trast to the gypsy moth, the. female brown-tail moth flies
freely, and when caught up by the wind is often transported
long distances. Mating takes place soon after the wings
are developed, and egg laying begins a few hours later.
The eggs are usually deposited on the under side of leaves
on the outside of the trees, preferably near the top. The
egg mass is much like that of the gypsy moth, although
smaller and more elongated. It contains from two hundred
to four hundred small globular eggs, thickly covered by a
mass of brown hair from the tip of the abdomen of the moth.
A typical egg mass (Plate 7) is about two-thirds of an inch
long and about one-fourth of an inch wide. If the moths
are disturbed while lajdng, or reach the edge of the leaf on
which the eggs are being deposited, they often change the
direction in which they move, or go to another place and
recommence the work. Whenever such changes occur, the
resulting cirg mass is more or less irrcoular in form. Occa-
sionally the eggs are deposited on branches and trunks of
trees, on fences, on the walls of houses and even on lamp
posts.
T/w Egg.
The egg is honey-yellow in color, of a more or less glob-
ular form, being about one-thirtieth of an inch in diameter,
and hatches in from fifteen to twenty days. The young
larvae feed at first on the leaf to which the egg mass was
attached, but soon migrate to other near-by leaves, always
returning at night to their original feeding place.
The Wmter Web (Plates 2, 13).
The hibernaculum or winter web of this insect is of such
a novel nature, at least to American entomologists, that a
detailed description of it may well be given at this point.
42 THE BROWN-TAIL MOTH.
In the fall the young larvae feed upon the epidermis of
the leaves onlv, causing them to turn as brown as though
scorched by fire, and while still young commence the dwell-
ing in which they hibernate during the winter (Plate 8).
These winter webs of the brown-tail moth, constructed at
the ends of the twigs, are from one to four inches in length
and from one to one and one-half inches thick, depending
upon the kind of tree on which they occur (Plate 6, Fig. 2).
The insect readily adapts its style of architecture to the ma-
terial at hand, making compact w^ebs on pear and willow,
and large open webs on maple and ash. Each web is com-
posed of a tenacious silken hibernaculum, enclosing leaves
from which the epidermis has been consumed, although the
outer leaves on the web may not have been attacked. The
webs are firml}^ attached to the twigs by stout bands of silk.
Almost invariabl}' the web commences where the egg clus-
ter was deposited, and remains of it can usually be found
on or in each web. Exit holes sometimes remain open on
the webs throughout the winter, but as a rule they are closed
by the matting together of the web under the influence of
rain. The webs consist internall}' of numerous layers of
silk, enclosing a great many small, irregular, silk-lined
chambers, which are often connected, and contain from six
to fifty larvae. The usual number found in the chambers is
about a dozen each. The larvaa are also often found in the
galleries in the web. The low^est part of the web is usually
full of fine black excrement, and the cast-off skins of the first
molt occur in many of the chambers. Twenty winter webs
of the brown-tail moth were opened Jan. 24, 1899, and
their inmates carefully counted, the webs being dissected
under a lens, so that none of the insects might be over-
looked. The webs contained respectively 253, 159, 253,
254, 223, 194, 182, 193, 84, 89, 47, 93, 299, 386, 674,
281, 664, 674, 802 (the latter being a double web),— a
total of 5,804, or an average of 290 caterpillars per web.
The Larva.
The newly hatched larva is about one-twelfth of an inch
long, with a shining black head, over the surface of which
are a few pale brownish-yellow barbed liairs. These hairs
Pl-ate 8.
Caterpillars of the brown-tail moth commencing' to spin their
■winter web on a pear twig.
THE BROWN-TAIL MOTH. 43
vary in length, but none of them are longer than the width
of the head. The body is dull yellow, but this is obscured
by the color of the tubercles, which are much darker than
the ground color of the body, some of them being black.
The tubercles are arranged as in the mature larva, and are
armed with Ijarbed spines like those on the head, except the
subdorsal row, which has smooth, sharp-pointed spines, dark
at the tip, lighter at the base, and about as long as half the
diameter of the body. The length of this stage is from four
to six da;ys.
The larva after the first molt is about one-fifth of an inch
long, with a shining black head, clothed with scattering pale
brownish-yellow hairs, as in the preceding stage. The
ground color of the body is dull yellowish, and the dark
color of the tubercles is so pronounced as to give a darker
appearance than in the preceding stage. The smooth, sharp-
pointed spines of the subdorsal row of tubercles are no longer
present, but are replaced by the ordinary barbed spines ; and
the subdorsal tubercles of the 5th and Cyth segments are cov-
ered with a short, dense tuft of chestnut-colored feathery hair.
The larva after the second molt changes but little before
hibernation, except in size. The head is black, and clothed
with barbed brownish-yellow hairs. The body is dark
brow^n, with two parallel longitudinal reddish-yelloAV lines
between the subdorsal tubercles, extending from the head
to the lOtli seo-ment, broken between the segments and also
on the 5th and 6th segments by the tufts of hair, which are
similar to those in the preceding stage. The coral-red
retractile tubercles on the top of the 10th and 11th seg-
ments appear after the first molt, and are present in all the
remaining larval stages, though at first they are of a light-
yellow color.
The larvfE stop feeding and go into hibernation in their
winter webs (Plate 14) early in September, some having
molted once, others twice and a few three times.
Emergence in the Spring.
The larvae generally emerge from the hibernating tents
from the 18th of March to the 20th of April, though the
time varies somewhat, according to whether the season is
44 THE BROAYN-TAIT. MOTH.
early or late. The earliest record of emergence was by Mr.
A. F. Burgess, who observed the young caterpillars emerg-
ing on March 18, 1898. By the last of April the larvaa are
usually well at work, feeding on the unfolding buds of the
pear and apple ; while those on the elm and oak do not fare
as well, since those buds open later in the season. The
larvae show but little method in feeding on the buds, simply
burrowing into and often entirely consuming them.
So far as has been observed, there are three molts after
emergence from the winter quarters before pupation. In
the quiet state, just before the first molt in the spring, the
larva is about one-fourth of an inch long, and differs only
in size and in having the ground color of the body a little
darker than it was before hibernation. They retreat into
the winter web, where they remain quiet for twenty-four
hours or more before molting.
The first molt in the spring occurs in about eight days
after the larva emerges from the winter web, when it dilfers
from the preceding stage in size, which is now about two-
fifths of an inch in length ; in the ground color of the body
now being a dark, smoky brown ; and in having much
longer spines, the longest of which are about three times
the diameter of the body.
The second spring molt occurs about the middle of May,
when the larva is about three-fifths of an inch lono-. This
stage is similar to the preceding, except that the ground
color and markinos are more like those of the full-grown
larva, though not nearly so bright.
The third spring molt occurs during the latter part of
May, when the caterpillar is from three-fourths of an inch
to an inch in length, and takes on the markings and charac-
teristics of the mature larva. It now has for the first time
the white branched hairs on the upper side of the lateral
tubercles, on segments 5 to 12 inclusive, and the nettling
hairs (Plate 9, Fig. 3) on the subdorsal and lateral tubercles
of these same segments.
The fourth and last spring molt occurs in the early part
of June, when the larva is from an inch to an inch and a
quarter in length. The head is pale brown, mottled with
THE BROWN-TAIL MOTH. 45
darker brown, and has light-brown hau*s scattered over the
surface. These hairs are finely barbed, and similar in struc-
ture to the long ones arising from the tubercles of the body
(Plate 9, Fig. 4). They are much shorter, however, the
longest being half the width of the head. The basal seg-
ment of the antennae and palpi is sordid white.
The body is dark brown or black, with numerous mark-
ings of a dull yellowish color, sometimes inclining to a dull
reddish. These markings are as follows : the thoracic and
anal shields, the latter often more or less dark brown in the
middle ; two parallel, irregular and more or less broken
lines along the middle of the back, represented on the an-
terior segment by two rows of spots of variable size ; a
small space around each of the tubercles ; many short, irreg-
ular, transverse streaks, most numerous on the sides and
beneath. A cluster of reddish-yellow, finely barbed hairs
of unequal length arises from each tubercle, while the sub-
dorsal and lateral tubercles on seo-ments 5 to 12 inclusive
are thickly covered with fine barbed hairs (Plate 9, Fig. 3),
which give these tubercles a dark-brown color and the ap-
pearance of velvet, under a lens. These are the " nettling
hairs." There is a fleshy, retractile, coral-red tubercle on
the middle of the back of segment 11, and a similar one in
th<? same place on segment 12. In one example these tuber-
cles were abnormal in size and position, one being larger
than usual, a little to the left of the dorsal line, and between
segments 10 and 1 1 ; while the other was less than half as
large as the first, and on the right side of the dorsal line,
more than twice as far from it and slightly farther forward
than the other.
The legs are dull reddish-yellow, with the claws and the
outside of the basal segment black. The spiracles are
vertically oval, and shining black. The surface of the body
under a one-half inch objective has a shagreened appear-
ance, with numerous fine, short hairs scattered over the
surface.
The thoracic shield on the top of the 2d segment (first
after the head) is wider in front than behind, and is divided
by a transverse impressed line into two parts. Most of the
46 THE BROWN-TAIL MOTH.
hairs along the front edge incline forward over the head.
They vary in length, the longest being about equal to the
width of the head. Those on the posterior part of this shield
are short, and sparsely scattered over the surface. A small
tubercle occurs behind the outer end of the thoracic shield,
and in line with the posterior part ; the next is larger,
oblique in front of the spiracle, and clothed with long hairs
which incline forward more or less ; the next tubercle is
about half way between the last and the leg. The 3d and
4th segments have three tubercles on each side in an obliciuc
row above the spiracular line, and two below. These two
are represented on each of the segments of the body after
the head, forming two subspiracular rows of tubercles.
Above the spiracular line, on each side of segments 5 to 13
inclusive, are two large, round, nearly equal-sized tubercles,
which may be called the subdorsal and lateral tubercles.
The hairs on the head and other parts of the body are similar
to those represented in Plate 9, Fig. 2, and the long ones
in Fig. 5, except those of a clear white color (Plate 9, Fig.
1) on the upper side of the lateral and a few on the outside
of the subdorsal tubercles, on segments 5 to 12 inclusive.
These hairs form a row of eight lunate white spots along
each side, which is the most striking characteristic marking
of the caterpillar.
The larvai spin their cocoons and pupate during the last
half of June, remaining in this stage about twenty days.
A favorite place for pupation is the leaves at the tips of the
branches, and not unfrequently a dozen or more larvae
assemble and spin a common web, within which each cater-
pillar forms its own cocoon and transforms into the pupa.
Another favorite place is under fences and beneath the edge
of clapboards. In 1897 Mr. Kirkland saw a mass of
cocoons nearly two feet across in the cornice of a house
on Vine Street, Somerville.
The cocoons are composed of grayish silk, so loosely
constructed that the pupa may be readily seen through it.
The pupa is about five-eighths of an inch long, of a dark-
brown color, with a conical spine at the end of the abdo-
men, this spine being armed with a cluster of minute hooks
THE BROWN-TAIL MOTH. 47
at the extremity. There are smooth, yellowish-brown hairs
scattered over the abdomen and top of the thorax, but none
on the antennas, leg or wing covers.
The Moths. '
As already noted, the moths emerge from the pupal stage
from the 1st to the 20th of July, the time varying, accord-
ing as the season is early or late. In 1898 the height of
the flying season was July 16, in 1899 it was July 8, while
in 1902 it was July 14. They are essentially night-flyers,
only a few being seen on the wing in the day time, while
the others remain at rest on the trees, fences and under side
of leaves. In an hour or two after sunset a few of the
moths venture forth, the number increasing as it grows
dark, and from 10 o'clock till midnight the moths fly in the
greatest numbers.
The average expanse of the wings of the males is one and
three-tenths inches, and of the females an inch and a half.
Head, thorax and wings snow white ; antenno3 white above,
with the under side and pectinations yellow ; abdomen,
above, smoky brown, more intense posteriorly. On the
end of the abdomen of the female is a lar<>:e jrlobular tuft
of hairs, which in difi'erent lights shade from golden yelloAv
to dark brown. In some females the hairs of the under side
of the head, thorax and abdomen are tinged more or less
with pale yellow. This is more pronounced in the males,
where, on the under side of the head, pectus and costa of
the fore wings, it is dark brown.
In July, 1897, a quantity of cocoons and pupae was
gathered and placed in a large glass-covered box, the moths
being removed as they emerged. The following table shows
the relative proportion of the sexes : —
48
THE BF^OWX-TAIL MOTIL
DATE.
Males.
Females.
July 7, .
5
2
8, . .
12
8
9, .
41
38
10, .
153
135
11, .
32
46
12, .
64
54
13, .
61
100
1-t, .
21
53
15, .
9
12
16, .
.
-
-
17, .
1
3
Totals,
399
451
Seven female motlis which had not deposited their eggs
were killed and carefully dissected. They were found to
contain eggs as follows: 344, 300, 217, 286, 257, 145,
209, — a total of 1,758, or an average of 251.1 per moth.
Distribution.
The principal distribution of the brown-tail moth takes
place at the time when the female moths are on the wing.
These insects fly freely, and have a habit of soaring upward
above the tree tops and buildings. When the moths in their
nocturnal flights have thus risen in the air, they are often
drifted by the wind over long distances. An excellent illus-
tration of the distribution of flying moths by air currents
was given by the high wind prevailing July 12-14, 1897, —
a time when the flying season of the brown-tail moth was at
its heisrht in Somerville and Cambridge. A few weeks pre-
vious the caterpillars had swarmed in nmltitudes in these
cities, and ih due time the white-winged moths emerged in
myriads. So plentiful were they at this time that arc lights
Plate 9.
Various forms of hairs from brown-tail motb caterpillars.
THE BKOWN-TAIL MOTH. 49
around Avhicli the insects hovered seemed indeed to be the
centres of miniature snow-storms. While the moths were
swarming on the night of the 12th, the wind came fresh
and strong out of the south to south-west, blowing steadily
at the rate of twelve to sixteen miles per hour. After mid-
night it increased in velocity to twenty miles an hour at 2
A.M. (July 13), twenty-five miles an hour at 8 a.m., twenty-
eight to thirt}^ miles an hour at noon, thirty-five miles at 5
P.M., and reached the maximum velocity of forty miles an
hour late in the afternoon. By midnight the gale had de-
creased to fourteen miles an hour, but increased again
rapidly, reaching a velocity of twenty miles an hour at 2
A.M., July 14, and forty-eight miles an hour at 8.40 a.m.,
then decreased to thirty miles at noon and twenty miles at
6 P.M. The day movement of the wind is not important,
as the moths are nocturnal, but it was soon apparent that
the wind of the nights of July 12 and 13 had transported
the flying insects into many cities and towns lying to the
northward, while to the south the distribution was limited.
Some two or three years were necessary before the increase
of the moth in the new localities was sufficient to call atten-
tion to its presence ; but by the fall of 1899 it had been found
scattered from Somerville northward to the State line at
Methuen and eastward to Seabrook, N. H., — a point some
forty miles distant from the original colony. In the si)ring
of 1902 the nests of the moth could be seen easily from
the car windows in every town along the eastern division of
the Boston & Maine Railroad from Boston to Portsmouth,
N. H. The occurrence of the moth at Kittery, Me., was
reported in 1899 by the late Prof. F. L. Harvey, Orono,
Me. The Kittery occurrence was doubtless due to the
transportation of household goods from a badly infested
Somerville estate at a time when the insect was in the co-
coon stage. Recently, Prof. James Fletcher, the distin-
guished Canadian entomologist, has reported the occurrence
of the mature moth at St. John, N. B. In the absence of
evidence to the contrary, he believes that the insect was
transported on the steamers plying between Boston and St.
John. This view is a logical one, for the trees on the islands
50 THE BROWN-TAIL MOTH.
in Boston harbor and along the north shore are generally
infested by the brown-tail moth. It is entirely probable
that moths attracted by the bright lights fly to and alight
on passing v essels, and in this way the insects already may
have been carried accidently to many seaports. The dan-
ger of spreading the moth by shipping is of course greatest
on the coastwise steamers, where the boats make landings
before the moths have laid their eggs and died.
When the moths are flying, they are strongly attracted to
light. In tracing the distribution of the moth in the winter
of 1898-99 it was found that the most promising places to
search for the insect were in the centres of population,
where electric and other lights were massed in greatest num-
bers. It is not difiicult to understand how the swarmino-
insects driven by the wind from the place of emergence fly
onward to the nearest mass of light. This tends to bring
about the infestation of the central portions of cities and
towns before the pest finds its way to the outlying residen-
tial or farminc: districts.
Again, the flying moths enter brightly lighted electric and
street cars. At the flying season warm weather is the rule,
and open car windows give the insect easy entrance. Mr.
Kirivland has repeatedly seen the female moths in rapidly
moving electric cars and on two occasions in local railroad
trains.
Aside from the principal means of distribution mentioned,
it is necessar}^ to consider the dropping of caterpillars on
teams, and the danger from nursery stock gfrown in the in-
fested district and shipped to customers living at a distance.
In common with other caterpillars, the brown-tail moth
larva? have a habit of spinning down on silken threads from
their feeding places, and hanging for some time suspended in
the air. Where they are feeding on street trees, they are
frequently intercepted by passing teams and are thus carried
from place to place. In the very thorough studies of the
distribution of the gypsy moth made by ]VIr. E. H. Forbush
some years ago, it was shown that one of the chief aids in
spreading the moth was the regular continued traffic of milk-
men, grocers and others. The spinning habits of the brown-
Plate 10.
EXPLANATION
\ j^TEWKSBUR
IcHtLMSFORD J ~^
\ /
\^^/"Y BILLERICA
^ \
• SBEDFORB^
CONCORD >^-r
VWAYLANDl
( \WESTO^f|
/^ \wELLE5LEr ^^
^--WicKYV
•^ ^' /^i ^-^ fl » \
s-'- **
\ /NEEDl
/ \ ^ Boston
^HULI
L
SHERBORIi' DOVER /wES>-^'^'^^'.^i^||5^
* ' _ .' wnnn V ' lllll i li '?■>• < . ^ -. ^
S^ -WEY-iHINCmM^
MAIN TREE' ,'^\-.-,<\^
S J CANTON \^
-"Mnorwood/
jWEY-iHINCWMl;^^
\ /' / S ^' CANTON \^ ,^^--- '^^
// N^olbrookI
r^V,
.■ ,..,,. pole/ ,
-lioRFOLK,^ ^^ SHARON VsTOutHTON
NORWELL
r'
\
Map sho^ving the rapidly increasing spread of the brovsm-tall moth.
THE BKOWN-TAIL MOTH. 51
tail moth do not differ materially from those of the gypsy
moth, and its distribution by teams is doubtless of frequent
occurrence.
Several eastern Massachusetts nurseries are more or less
infested by the brown-tail moth, and there is constant dan-
ger that a small caterpillar web may be sent out with trees
to some distant locality, and there establish a moth colony.
This matter is one that has received special attention from
the efficient State Inspector of Nurseries, Dr. H. T. Fernald ;
while the proprietors of infested nurseries are taking every
precaution to insure the destruction of moths on their
grounds and prevent its spread elsewhere.
At the present writing the moth is known to occur in
Massachusetts at Scituate on the south, westward to Brock-
ton, Hudson and Stow, northward to Methuen and eastward
to the sea. The occurrences at Kittery, Me., and St. John,
N. B., have been mentioned. South-eastern New Hampshire
is also generally infested, and we fear in the course of a few
decades the pest will have found its Avay over the greater
part of New England. The neglect of a moth colony on an
infested estate results in the spreading of the pest to adjoin-
ing places ; neglect on the part of generally infested towns
leads to the swarming of the moth and its dispersal into
neighboring municipalities. The ease with which the moth
becomes distributed gives an additional reason for thorough-
ness in stamping out incipient colonies.
The tabulation below gives a good idea of the rapidly
increasing spread of the insect. Since 1899 no accurate
records of the distribution of the moth have been kept.
The area infested in 1896, the year previous to the discovery
of the moth, was determined by the finding in the spring of
1897 of the winter webs of the previous year.
Square Miles.
Area infested, fall of 1896, 29
Area infested, fall of 1897, . , ,
Area infested, fall o,f 1898, .
Area infested, fall of 1899, .
Area infested, fall of 1902, estimated,
158
448
928
1,600
52 THE BROWN-TAIL :\10T1I.
Natural Enemies.
One reason why the brown-tail moth is so very injurious
in Massaehusetts is found in the lack of the parasitic ene-
mies which hold the insect more or less in check in its
original home. As 3^et our native parasites have not adai)ted
themselves to this new caterpillar, and, freed from the
checks that control it at home, it here causes a greater and
longer-continued damage than is common in Europe. Of
the Hjniienopterous parasites connnon to caterpillars of this
class, Pimjjia tennicornis Cr. and Phoiogenes hehe Cr. have
been bred in some numbers from the cocoons. The greatest
natural aid in destro3ang the brown-tail moth seems to be
the tiny parasite Dir/lochi's omnivora AYalk. Large num-
bers breed in a single i)upa, and, emerging early in the
season, attack other larvai and pupjv, and thus prevent their
development into moths. From a single pupa 158 Diglocliis
were obtained in July, 1898, while from a mass of about
four quarts of cocoons over three thousand of these para-
sites emerged during the same month. Of the dipterous
parasites, the only one determined is EupJiorocera clari-
pennis Macq. So far as we have observed, the caterpillar
is only slightly attacked by parasites of this class.
The number of predaceous bugs which assemble on trees
infested with the brown-tail moth early in the spring is
quite remarkable. These bugs, hibernating in sheltered
localities, eagerly seek food in the first Avarm days of
spring. The brown-tail moth caterpillar is the largest
insect of its kind which is at all abundant early in the
season, and the predaceous bugs readily adapt themselves
to it. The result is greatly to the advantage of the bugs
and to the farmer. May 1, 1899, with the thermometer in
the shade at 90° F., six trees infested with the brown-tail
moth were examined, with the result that the following
number of predaceous insects were found feeding upon the
small caterpillars : 113 Podisus seneventris, 36 Podisus
jplacidus, 2 Mihjas cinctus, 1 Liotropis humerah's, 1 w^asp,
PoJistes pallipes; in other Avords, on the six infested trees
there Avere 152 predaceous bugs at work destroying the
THE BROWX-TAIL MOTH. 53
larvce, or an average of 25.2 bugs to a tree. Many of the
buofs were matino-, and it was not unusual to see two bugs
both feeding on a single larva. The was}) made a business
of tearing into the webs, extracting the lai'vse, rolling them
up into a l)all by means of the fore-feet and jaws, and carry-
ing them oil'.
In the spring of 1899 Mr. Kirkland placed three webs of
the brown-tail moth on as many wild cherry trees in rear
of his house at Maiden, with a view to .studying the habits
of the caterpillars, the locality being alread}' somewhat
infested. As soon as the larva? emerged and commenced to
feed, predaceous bugs of the genus Podisuf< appeared, and
in less than a fortnight had completely wiped out each
caterpillar colony.
The huml)le toad must also be reckoned in the list of the
enemies of the brown-tail moth. During the early sum-
mer, when the caterpillars are swarming, large numbers are
eaten by toads. Seven toads taken on infested estates May
24-26, 1897, contahied respectively 7, 5, 0, 3, 8, 3 and 12
brown-tail moth larva?. The work of toads is more notice-
able, however, during the flying season, when they assemble
under arc lamps, and devour the fluttering moths as they
fall stunned or injured from the lamps above. Four toads
taken under arc lamps at Somerville on the night of July
16, 1897, contained respective!}^ : 11 male moths, 4 female
moths ; 6 male moths, 4 female moths ; 7 male moths, 4
female moths ; 9 male moths, 8 female moths.
Bats also are worthy of mention among the natural ene-
mies of the moth. Where the moths swarm thickest around
the lamps, the bats are constantly in evidence, their noise-
less work being easy to trace by the falling of white moth
wings. At Maiden, on the night of July 14, 1898, several
bats were noticed destroying the moths around an arc light.
The following morning over two hundred wings of the brown-
tail moth were counted on the ground beneath that particu-
lar lamp. Allowing four wings to each moth, this would
indicate the destruction of fifty imagoes by the bats at this
one point.
It occasionally happens that the young hibernating cater-
54 THE BROWX-TAIL MOTH.
pillars are de.stro3'ed earl}' in the fall by a fungus or mold
which develops in the webs. The caterpillar destruction
from this cause is most noticeable during a fall that is espe-
cially damp and rainy ; we have never noticed it taking
place in a dry fall. It is most common in those webs
which arc spun on trees with large -leaves, such as the ma|)le
or horse-chestnut. These Avebs are of necessity more open
than those spun on trees with smaller leaves, such as the
pear or willow. The i-ain penetrates these larger and more
open webs, and dampens the masses of excrement which are
found in many of the chambers of the web. It is evident
that when these webs become thoroughly dampened inside,
the molding and death of the caterpillars usually occur.
Electric Ltylils.
Although electric lamps can hardly be classed among the
" natural" enemies of the moth, they exercise none the less
a ver}^ important influence in destroying the swarming moths
during the flying season. AVe have pointed out in another
place how these lamps, by attracting the moths, materiaWy
increase their distribution. It is well to shoAV, therefore,
the good done by the lamps in destroying the swarming
insects. The moths come out in large numbers soon after
the lights are turned on, and from ten o'clock to midnight
the swarming is at its height. The moths encircle the lamps
at times in such numbers as to somewhat obscure the light.
The bodies of those killed by the electric current drop con-
tinually, and by morning the ground under the lamps in the
worst-infested regions is liberall}' sprinkled with bodies of
dead moths. Counts of dead moths under five arc lamps
were made at four o'clock in the morning on July 16, 1897,
with the following results: lamp No. 1, 236 males, 71
females; lamp Xo. 2, 29 males, 11 females; lamp No. 3,
7 males, 4 females ; lamp No. 4, 3 males, 4 females ; lamp
No. 5, 22 males, 2 females.
Lamp cleaners report that they often find a quart or more
of dead moths in the lamps early in the morning. Mr. Kirk-
land spent several nights in 1897-98 watching the swarming
of the moths, and found that towards morning many of the
P»late 11.
Damage by tiny caterpillars of brown-tail moth in fall.
Photo, Meiiford, Mass., Sept. IS, 1899.
THE BROWN-TAIL MOTH. 55
arc lamp globes would become more or less clogged by the
bodies of the insects. As soon as daj^light breaks, however,
the English sparrows swarm to the lamps and feed upon the
moth bodies. They also carry them to their young. A
remarkably short time suffices for these birds to remove a
quart or more of the moths from the lamp globes. While
the old birds evidently enjoy the moths as a morning meal,
they also carry them in large numbers to their young.
Birds as Destroyers of the Brown-tail Moth.
Birds play an important role in checking the spread of
the brown-tail moth. While their attacks are perhaps more
conspicuous while the insect is in the moth stage, it is
probable that the greatest number of insects are destroyed
in the larval form, at which time many species of birds not
only consume the caterpillars, but carry them to their
young. Armed as these larvae are with an abundant growth
of nettling hairs, it Avould seem that they would prove
distasteful morsels for the birds, and be largely protected
from their attacks. This, however, is not the case ; the
same species of birds that feed on other hairy caterpil-
lars, such as the tussock moth, forest tent caterpillar or
gypsy moth, readily adapt themselves to the brown-tail
moth caterpillars. Of the birds feeding on the caterpillars,
the yellow-billed and black-billed cuckoos and Baltimore
oriole are worthy of special mention. They are common
visitants to infested trees, feeding freely on the insects, and
carrying them to their young. They arrive in their sum-
mer migration when the caterpillars are about two-thirds
grown, and make repeated visits to the infested trees, feed-
ing particularly on the masses of insects clustered for
molting. As is well known, the cuckoos are formidable
enemies of hairy caterpillars. Their services in destroying
the common tent caterpillar of the orchard are of highest
value, and alone should entitle them to the good- will of the
farmer or property owner ; and this statement is also true
of the Baltimore oriole. Of the other birds which feed on
the larvae, the yellow-throated vireo and blue jay are worthy
of special mention.
56 THE BROWN-TAIL MOTH.
It is, however, when the moths are emerofino^ that the
lajMiian notices more particularly the work of birds in
checking the increase of this insect. The white moths leave
their cocoons and remain in situations more or less exposed
until their wings have developed. As a result of the habit
of the caterpillars in spinning their cocoons in a common
mass, there will often be a large number of moths within a
small area on a fence, house wall or other sheltered locality.
The birds soon locate these favored spots, and often con-
sume the moths even before their wings have expanded. In
this work of moth destruction the kingl)ird and some of the
^catchers figure to a limited extent, but the most formid-
able enemy of the mature moths is the notorious English
sparrow. That this l)ird, Avhose evil habits in driving out
native insectivorous birds are so well known, should show
this distinctW beneficial trait, may be a matter of surprise
to many students of nature ; but the fact remains tliat the
English sparrow, M'ith its numerous progeny, exerts a great
and beneficial influence in checking the moth in our thickly
settled districts, — places where natural checks are often
most deficient.
Jul}^ IG, 1897, the time when the moths were notably
thick at Somervillc and Cambridge, Mr. Kirkland observed
whole flocks of English sparrows following along the line
of fences and carefull}^ searching for the moths, which when
found were greedily devoured. The sides of the pickets
and even the bottom of the rails were carefully examined
by these sharp-eyed moth hunters, and all moths of either
sex found were consumed.
The sparrows do not confine their attentions to hunting
for live moths, but also act as scavengers in removing from
the arc lamps the masses of moths which accumulate in the
globes over night. At 10.30 p.m., July 14, 1897, an arc
lamp at Maiden around which the moths were swarming
was from one-fourth to one-third full of the dead bodies of
the moths. Wishing to make a count of the number of
moths thus destroyed by the lamp, Mr. Kirkland visited it
at 5.30 the following morning ; but at that hom* the sparrows
were actively feeding on the moths in the lamp globe, and
THE BROWN-TAIL MOTH. 57
also carrying them to their young. July 16 other arc lamps
Avcre examined at 4.30 a.m., but even at that time the birds
had anticipated the observer, and were carrying off the
moths in large numbers. At 5.30 the sparrows had emptied
the o-lobe of moths, and also consumed the insects on the
srround underneath it. It was observed at 4.30 that there
were sixteen male and two female moths on the lamp pole,
but at 6 A.M. the birds had consumed all of them.
On the afternoon of July 16, at a time when the moths
were still emerging, a drive through the worst-infested dis-
tricts showed only three brown-tail moths on lamp poles or
tree trunks. There were plenty of the moths in sheltered
places in the trees and under the leaves of rank herbage on
the ground, bvit those in conspicuous positions had been de-
stroyed.
Below is given a list of birds known to feed u}X)n the
brown-tail moth in any of its stages : —
Red-eyed vireo. *
Yellow-throated vireo.
Black-and-white warbler.
Yellow-billed cuckoo.
Black-billed cuckoo.
Kingbird.
Blue jay.
Baltimore oriole.
Rose-breasted grosbeak.
Indigo bird.
Scarlet tanager.
Chestnut-sided warbler,
American redstart.
Chickadee.
American robin.
English sparrow.
Food Plants.
That the favorite food of the brown-tail moth is the pear
tree is very unfortunate, since there are few places in the
United States where pears are more successfully cultivated
than in eastern Massachusetts, — indeed the pear orchards
of Revere and Arlington have a reputation not limited by
State boundaries. Next to the pear the apple is preferred
by the caterpillars, although they breed freely on stone fruits,
and also on the elm, maple and several species of oak.
When the caterpillars swarm forth from overcrowded col-
onies, they seem to exercise but little selection in the matter
of food, but feed generally upon all deciduous trees, on many
shrubs and even upon herbage. A list of plants upon which
the caterpillars have been found feeding is given below : —
58
THE BROWN-TAIL MOTH.
Barberry, — Berberis vulgaris.
Bass wood , — Till a Ameri-.
cana.
European linden, — TiUa Eu-
ropcea.
Horse-chestnut, — ^ s cul ii s
Hippocastanum.
Sugar maple, — Acer sacchar-
in um.
White maple, — Acer dasycar-
pum.
Cut-leaved maple, — Acer dasy-
carpum, var. Weirii.
Red maple, — Acer rnhrntn.
Box elder, — Negundo acero-
ides.
Variegated box elder, — Ne-
gundo aceroides, var. rarie-
gata.
Stag-horn sumach, — lihus tif-
phina.
Smooth sumach, — Rhus glabra.
Smoke tree, — Rhus Cotinus.
Locust, — Robinia Pseudaca-
cia.
Beach plum, — Prunus mari-
tima.
Wild red cherry, — P r u n u s
Peiinsylvanica.
Choke-cherry, — Prunus Vir-
giniana.
Damson plum, — Prunus do-
mestica.
Purple-leaved plum, — Prunus
Pissardi.
Apricot, — Pru7ins Armeniaca.
Japanese plum, — Prunus Ja-
ponica.
Meadowsweet, — Spircea sali-
cifolia.
Thimbleberry, — Rubus occi-
dentalism
Dwarf wild rose, — Rosa lu-
cida.
Rose, — Rosa nitida.
Choke-berry, — Pyrus arbuti-
folia.
Pyrus pinnatifida.
English hawthorn, — Cratcegus
Oxyacantha.
Paul's thorn, — Cratcegus coc-
cinea, var. Paidii.
Cockspur thorn, — Crataegus
Crus-gaUi.
Shad bush, — Amel anchier
Canadensis.
Quince, — Cydonia vulgaris.
Japan quince, — Cydonia Ja-
pan ica.
Common red currant, — Ribes
rubrum.
Black currant, — Ribes nigrum.
Gooseberry, — Ribes g ros s n -
laria.
English gooseberry, — Ribes
JJva-crispa.
Witch hazel, — HamamelisVir-
giniana.
Flowering dogwood, — Cormis
florida.
Cornus mas.
Arrowwood, — Viburmim aceri-
folium.
Arrowwood, — Viburnum den-
tatum.
Black haw, — Viburnum i^ru-
nifolium.
Wiegelia rosea.
Aster puniceus.
Sweet pepperbush, — Clethra
alnifolia.
White ash, — Fraxinus Ameri-
cana.
Red ash, — Fraxinus pubescens.
THE BROWX-TAIL MOTH.
59
Blue ash, — Fraxiiias quadran-
gulata.
Black ash, — FnixiiuxH sambti-
cifolia.
Common lilac, — Syringa vul-
garis.
Japanese lilac, — Si/ringa Ja-
2)onica.
Slippery elm, — Ulmus fulvus.
White elm, — Ulmus Ameri-
cana.
Cork elm, — Ulmus racemosa.
English elm, — Ulmus campes-
tris.
Scotch elm, — Ul m u s m o ti-
tan a.
Red mulberry, — Morns rubra.
Tartarian mulberry, — Mo r u s
Tartarica.
Sycamore, — Platanus occiden-
tal is.
Black birch, — Betiila lenta.
Yellow birch, — Betula lutea.
White birch, — Betula populi-
folia.
Paper birch, — Betxda piapyrif-
era.
Cut- leaved birch, — Betula alba,
var. laciniata.
Hop-hornbeam, — Ostrya Vir-
ginica.
White oak, — Qnercus alba.
Swamp white oak, — Qnercus
birolor.
Red oak, — Quercus rubra.
Scarlet oak, — Quercus coccinea.
Black oak, — Quercus coccinea,
var. tinctoria.
Pin oak, — Quercus jJalustris.
Scrub oak, — Quercus ilicifolia.
Chestnut, — Castanea sativa,
var. Americana.
Blue beech, — Carpinus Caro-
liniana.
American beech, — Fagus fer-
ruginea.
Purple beech, — Fagus sylva-
tica, var. purpiurea.
Crack willow, — Salix fragilis.
White willow, — Salix alba.
Weeping willow, — Salix Baby-
lon ica.
Heart- leaved willow, — Sal ix
cordata.
Remedies.
Web Destruction.
In the case of the brown-tail moth, action looking to the
prevention of damage by the caterpillars is of more impor-
tance than the application of remedies after the insects have
commenced feeding. With tliis insect the traditional " ounce
of prevention" is worth many "pounds of cure." For
nearly six months, or, generiUy speaking, from the first of
October to the first of April, these insects are massed to-
gether within their silken winter webs. These webs, as
already pointed out, are attached to the tips of the twigs,
are grayish-white in color, and easily seen when the foliage
BO THE BKOWN-TAIL MOTH.
has fallen from the trees. lu the case of either fruit or
shade trees of ordinary size, nothing is easier than to cut off
and burn the webs. The success of this operation was early
discovered, and European treatises on the moth make par-
ticular mention of this method for combating it. The well-
known European laws concerning the brown-tail moth lay
particular stress upon this destruction of the winter webs ;
and, in ftict, it is the essential feature of the famous French
law of " echeniUage.'''
For the work of web destruction there will be required
ladders of suitable length, stout clothing, and some form of
pruning shears attached to a long handle, the so-called
""Water's pruner"' being the one generally used. It has
been found that this work can be done more rapidly and
thoroughly b}^ two men, one on the ground to discover and
point out the webs, the other cutting them off while in the
tree. All wxbs removed in this manner should be carefully
gathered in bags or baskets, and destroyed by fire. A care-
ful series of experiments made at the insectary of the gypsy-
moth conmiittee in the winter of 1897-98 showed that, if
these webs are left upon the ground, the vitality of the in-
sects is not destroyed by the action of the elements, and
that a considerable percentage of them will emerge un-
harmed the following spring. In this experiment, as con-
ducted by ]Mr. Kirkland, a number of brown-tail moth webs
were spread upon the ground in a single layer in the fall,
and covered with a piece of coarse poultry netting ; thus the
webs were exposed throughout the winter to rain, snow,
freezing and thawing. The following spring, as soon as the
caterpillars in webs on fruit trees near by began to show
.signs of activity, the webs were taken from the ground
(April 1.5, 1899) and each placed in a glass-covered box.
The larvffi commenced to emerge soon after the webs were
brought into a warm room, and continued to come out until
April 22. April 26, as no more larvfe came from the webs,
they were destroyed. In all, 49 webs yielded larvae, while
from 82 webs no larvse emerged. Careful records were kept
of 8 webs from which caterpillars emerged, in order to de-
termine the number of larvae coming from each web. The
results are tabulated below : —
Plate 12.
Fall web worm and brown-tail moth contrasted. On left, loose open
w^eb of web w^orm; on right, compact w^eb of broAw^n-tail moth.
Photo, Maiden, Mass., Aug. 9, 1890.
THE BROWN-TAIL MOTH.
61
This gives us an average of 26.3 larva? per web emerging
unharmed ; the average normal web contains about 290
larvte.
It is preferable, where circumstances permit, to burn the
webs in a furnace or stove, thus insuring their complete de-
struction. Where the webs are burned in a bonfire in the
field, it often occurs that a part become covered with ashes
and are not consumed. In a case noticed bj one of the
writers, some years ago, a number of webs that had been
partly scorched in a bonfire were still found to contain liv-
insf insects. Silk is an excellent non-conductor of heat, as
well as of cold ; and in this case, while the webs protected
the caterpillars from the rigors of winter, they also preserved
a part of them unharmed from the action of fire.
/Spraying.
There will ahva3's be cases where the work of web de-
struction has been neglected, from one cause or another, —
too often from the indolence of the property owner. When
the caterpillars emerge in the spring and commence feeding
on the young buds and leaves, the best remedy is to spray
the tree promptly and thoroughly ^vith arsenate of lead,
using 3 or 4 pounds to 50 gallons of water. The insecticide
62 THE BROWX-T.UL MOTH.
should be thoroagblv applied to the leaves, particularly in
the part of the tree where the insects are feeding. In cases
where trees cleared of the caterpillar webs stand near in-
fested trees, they niay also be preserved from damage by
the migrating caterpillars by a thorough spraying, as above
indicated. AVhere arsenate of lead cannot be obtained,
Psuis green nay be used, at the rate of 1 poand to 150 gal-
lons of water, keeping the mixture well agitated while
spraying. In the case of shade trees, this spraying should
be done as soon as the foliage develops : and the same rule
holds ffood with fruit trees, where the insects are abundant.
If the trees are not badly infested, however, it is otien de-
sirable to wait ontil after the blossoms have fiJlen before
spraying, thus securing a doable benefit by destroying the
caterpillars of the bcown-tail moth, and also preventing
dama*^ to the fruit bv the codling moth.
Where neither the web destruction nor early spraying
has been practised, it often occurs that the caterpillars,
nearly full grown, are found devastating the foliage of the
neglected trees. Where the insects are nearly mature,
spraying with arsenical poisons does not always give satis-
&ctory results, for the reason that a great many of the in-
sects disturbed by the spraying wiU pupate without feeding
longer. In such cases it is more satisfactory to prepare a qtan-
tity of strong kerosene emulsion, then _pir the caterpillars
from the trees by beating the latter with poles. The insects
Mlino^ to the STound should be thoroushlv drenched with
the kerosene emulsion, applied either with a sprayer or
fiv>m a watering-pot- Trees freed from the caterpiQais in
this way, and also non-infested trees standing near those on
which the caterpillars are feeding, may be easily preserved
fi\)m ^mage by banding them with some sticky mafenal^
such as the Grerman raupenleim. or its American sobstitute.
bodlime. or even with tar r s ink. These malenads,
properly applied, form, a sticky >ver which the insects
cannot pai^.
THE BROWN-TAIL MOTH. (>;i
Banding.
In using tar or printer's ink, it is best to first Jii)ply a
small band of cotton Avaste or wool, then tack over it a hand
of tarred paper, to which the ink or tar is applied directly.
These bands should be repainted at intervals of a few days,
until the caterpillar season has passed. The bands of lime
(either raupenleini or bodlime) are applied directly upon
the bark. The bands should be from two to three inches
wide, one-half inch thick at the bottom, tapering upward to
the bark, in order \p shed rain. The bottom of the band
should be shaped to form a sharp shoulder. It is the ten-
dency of insect lime to yield up a small <iuantity of oil under
the influence of the sun, thus keei)ing the lower edge of the
band always moist and sticky, and presenting an insur-
mountable barrier to the insects.
When the insects have j)U})ated, the cocoons may be
gathered and destroyed, although this work is usually
attended with a severe nettling of the skin, described in
another place. Cocoons and pupa> thus gathered should be
placed in a barrel covered with mos(|uito bar, so that the
parasites contained in them may escape, while the moths
will be unable to pass through the netting. In the case
of the brown-tail moth this precaution is an excellent one,
as this insect is extensively parasitized in the pupal stage.
Second Brood.
It often occurs in badly infested localities that the small
caterpillars hatching from the eggs occur in sufficient num-
bers to partially or entirely defoliate the infested trees.
This damage does not occur on trees which have been
thoroughly sprayed with arscMiate of lead the preceding
summer. Where the insects are numerous, a fall si)ray'ing
with arsenate of lead is recommended, except in the case
of trees in fruit, since, where the fruit is within a few weeks
of ripening, it is not advisable to use the very adhesive as
well as very poisonous spray. (Plate 11.)
64 THE BKOWX-TAIL MOTH.
Insecticides.
For the work of spraying the foliage, no poison is more
effective than the arsenate of lead. This material is of light
specific gravity, hence remains well suspended in the spray-
ing solution, and insures an even distribution on the foliage.
It does not kill cjuite as (juickly as Paris green, but is very
etfective against the insects when used in the i)roportions
directed. It has two special advantages, in that it sticks to
the foliage tenaciously throughout the season, and will not
scorch or injure the most delicate leaves. It is slightly
more expensive than Paris green or London purple, if the
first cost of the material only is considered. On the other
hand, as one spraying is often sufficient to preserve a tree
unharmed from leaf-eating insects for an entire season, while
repeated sprayings of Paris green are necessary, the arsenate
of lead often proves the cheaper insecticide.
How made.
Arsenate of lead may be prepared by dissolving separately
3 parts commercial nitrate of lead and 1 part connnercial
arsenate of soda and pouring the two solutions together,
when the arsenate of lead is flung down as a dense white
precipitate. This fornuila is based upon the average grade
of nitrate of lead containing 66.5 per cent, lead oxide, and
arsenate of soda containing 59.8 per cent, arsenic oxide.
Owing to the difficulty in obtaining these chemicals in small
quantities at a fair price, and the uncertainty as to their
purity, the small user will do well to piu-chase some one of
the prepared forms of arsenate of lead now oflered in the
market, instead of attem})ting to manufacture the insecticide.
Owing to the increasing use of arsenate of lead for spraying
purposes, several reliable manufacturers have put it upon
the market in the form of a paste, which is ready for use as
soon as water is added, thus being at once convenient and
inexpensive.
If Paris green is used, a strength of 1 pound to 150 gal-
lons of water will give good results, and the i)roportion of
poison should not be greater than 1 pound to 100 gallons,
Plate 13.
Winter webs of brown-tail moth on English oak.
Photo loaned by Chas. Bradley, Supt. Farm School, Thompson's Island.
THE BROWN-TAIL MOTH. 65
otherwise burnino- of the foliao-e will occur. In usino- Paris
green, it should be borne in mind that this insecticide has a
high specific gravity and settles rapidly in the spraying
tank, hence it should be stirred continually while being-
applied.
Kerosene emulsion, useful in destrojdng caterpillars jarred
from trees, and on fences, walks, etc., is made by dissolving
^ pound hard soap in 2 quarts of water, and adding to the
solution, while hot, 1 gallon of kerosene oil, stirring the
whole, or pouring it rapidly from one pail to another until
a stable white emulsion is formed. This emulsion for use
on the caterpillars should then be diluted at the rate of 1
part emulsion to 5 of water. At this strength there will be
some injury from the kerosene to grass and other foliage,
but the effect on caterpillars will be more satisfactory than
where the normal dilution of 1 part to 9 of water is used.
Apparatus.
The damage by the brown-tail moth is as severely felt in
proportion to the value of the crop in the kitchen garden as
on the farm. In fact, owino- to the scarcity of native in-
sect-eating birds in our cities, injury by caterpillars of
this class is sometimes more severe in cities than in the
open country. While the city owner requires the same
spraying materials as are used on the farm, his needs in the
line of apparatus are much less.
For use in a kitchen garden or on a small estate, excel-
lent results in spraying can be obtained from a brass
syringe, such as is commonly used in greenhouses for
showering plants. A suitable syringe can be bought for
about $4, and by its use vegetables and fruit trees of good
size may be sprayed satisfactorily.
On larger estates, and particularly where shrubbery has a
prominent place, no outfit is more convenient and generally
useful than a copper knapsack spray pump. We might add
that nothing is more wearisome to the flesh than to carry
one of these outfits on a hot day, but such labor often paj^s
big dividends. The writers would advise against the pur-
chase of galvanized-iron knapsacks ; these soon rust out,
66 THE BROWX-TAIL MOTH.
two years being about tlio limit of their usefulness. On the
other hand, a copper knapsack pump, costing at the start
about $12, if properly cared for will last ten or fifteen
years. It is important that it be thoroughly washed with
clean water after using.
In orchards and for general work against the brown-tail
moth and other insects, a substantial spray pump, mounted
on a 50-gallon cask, is a necessity. Such a pump should
have brass working parts, an effective agitator, and an air
chamber of ample capacity to equalize the flow of the spra3^
The price of pump and cask ought not to exceed $12 or $15.
In addition will be needed 50 to 100 feet Avhite cotton hose,
costing about 10 cents per foot ; an 8 or 10 foot spray pole
extension, $1; and a Vermorel nozzle, 60 cents, — these
figures being approximately correct for present market con-
ditions. If desired, the spray pole can be made by any
plumber from a piece of one-fourth-iuch gas pipe. At the
lower end a hose nip (reducer) should be inserted to receive
the end of the hose ; the other end should be threaded to
screw directly into the nozzle.
For extensive spraying operations, such as are necessary
in large orchards, parks, and especially where tall shade
trees are to be sprayed, larger and stronger pumps will be
required. In these operations it is often desirable to use
two or more lines of hose, often against a head of seventy-
five to 100 feet. A pump suited for this work must have
cjdinders of ample capacity, a large air chamber and a rigid
frame and base. From $25 to $30 will cover the cost of
such a pump. Other details will be about as follows : suc-
tion hose, fittings, strainer, etc., $5 ; 200 feet hose, $20 ; two
spray poles, $2 ; two nozzles, $1.20 ; 150-gallon hogshead,
$1.50. An outfit of this class is suited for the largest
spraying operations, such as park or city work, as well as
for extensive orchard sprayings. At Dedham, Ipswich,
Bridgewater, Lawrence and elsewhere street elms have been
sprayed with outfits of this description, with highl}^ satis-
factory results.
Plate 14=.
Winter -webs of brown-tail moth on American elm and rock maple,
Medford, Mass.. Nov. 20. 1899.
THE BROWX-TAIL MOTH. 67
Hoiv to Spray.
One might suppose that the spraying of a tree or a plant
was a simple operation, requiring but a modicum of skill
and intelligence. This view doubtless is responsible for a
large part of the failures in spraying, for particular care and
attention must be given both to the mixing and the appli-
cation of the insecticide materials, in order to obtain satis-
factory results.
Assuming that the proper materials in proper quantities
have been obtained and mixed according to directions, a
suitable outfit provided, and the water used carefully
strained, the work of spraying may be commenced.
Where trees are treated, spraying should commence at
the top. If the wind is blowing, the work should be car-
ried on from the windward side. Often in a breeze of low
velocity large trees can be thoroughly sprayed from the
windward side alone, the mist being drifted on the air.
The spray should be applied as a fine mist, never in a
stream. The dew remains on the leaves ; the rain runs ofi".
The same is true of spraying ; a mist adheres, but drops
run off. The nozzle should have a very small aperture, and,
if backed by a pump of adequate power, the spra}^ will burst
forth as a fine mist, Avhich should be allowed to diffuse in
the air before striking the foliage. Hence it is desirable to
hold the nozzle a few feet from the leaves to be treated.
In all cases spraying should cease as soon as the foliage
begins to drip.
Spraying Experi:\lents.
Numerous experiments with insecticides on brown-tail
moth larvse were carried on at the insectary of the gypsy
moth committee. So thoroughly, however, had this field
of experimentation been covered in the case of the gypsy
moth, that few additional facts of value were discovered.
Certain field experiments upon the brown-tail moth cater-
pillars are of particular value, however, as showing results
obtained under the actual conditions which confront the
property owner having infested trees.
In May, 1898, there were secured for experimental pur-
68
THE BROWX-TAIL MOTH.
poses a large number of pear trees, from ten to fifteen feet
high, standing on an estate in the southern part of Maiden.
These trees were thoroughly and quite uniforml}^ infested
with the brown-tail moth, and the caterpillars had emerged
and commenced feeding, being at the time of the experi-
ments in the second and third molts. In each case these
trees were sprayed with various insecticides, as given below.
In the case of arsenate of lead, the quantities mentioned
represent the actual dry arsenate of lead contained in the
ingredients used.
Field Experiments.*
1. Arsenate of lead, 1 pound to 150 gallons of water: —
May 19,
May 20,
May 21,
May 22,
May 23,
May 24,
May 25,
May 26,
sprayed,
no results.
no results,
ceased feeding.
50 per cent, dead
May 27,
May 28,
May 29,
May 30,
May 31,
June 1,
June 2,
90 per cent. dead.
all dead.
2. Arsenate of lead, 2 pounds to 150 gallons of water : —
May 19,
May 20,
May 21,
May 22,
May 23,
May 24,
May 25,
May 26,
sprayed,
no results,
no results,
ceased feeding.
50 per cent. dead.
May 27,
May 28,
May 29,
May 30,
May 31,
June 1,
June 2,
90 per cent. dead.
all dead.
3. Arsenate of lead, 5 pounds to 150 gallons of water: —
May 19,
May 20,
May 21,
May 22,
May 23,
May 24,
sprayed,
no results,
no results,
ceased feeding.
80 per cent. dead.
May 25,
May 26,
May 27,
May 28,
May 29,
. all dBad.
4. Arsenate of lead, 10 pounds to 150 gallons of water : —
May 19, .
. sprayed.
May 23, .
. 80 per cent. dead.
May 20, .
. no results.
May 24, .
.
May 2'1, .
. few dead.
May 25, .
.
May 22, .
. 50 per cent. dead.
ISIay 26, .
. all dead.
* One pound arsenate of lead as used in these experiments is equal to about
, two pounds commercial arsenate of lead paste.
THE BROWN-TAIL MOTH.
69
5. Paris green, 1 pound to 150 gallons of water : —
May 19, .
sprayed.
May 26, .
70 per cent. dead.
May 20, .
no results.
May 27, .
-
May 21, .
no results.
May 28, .
-
May 22, .
10 per cent. dead.
May 29, .
90 per cent. dead.
May 23, .
50 per cent. dead.
May 30, .
-
May 24, .
-
May 31, .
-
May 25, .
— -
June 1, .
all dead.
6. Scheeles'
green, 1 pound to 150
gallons of water : —
May 19, .
sprayed.
May 27, .
- -
May 20, .
no results.
May 28, .
-
May 21, .
no results.
May 29, .
75 per cent. dead.
May 22, .
. 5 per cent. dead.
May 30, .
_
May 23, .
. 25 per cent. dead.
May 31, .
-
May 24, .
.
June 1, .
95 per cent. dead.
May 25, .
.
Jvme 2, .
.
May 26, .
. 50 per cent. dead.
June 3, .
. all dead.
In the fall of 1898, while the newly hatched caterpillars
were still feeding, a number of trees at Maiden were
sprayed with arsenate of lead at the rate of 12 pounds to
150 gallons of water. As the webs were nearly formed at
this time, it seemed desirable to keep a certain number of
them, to determine whether the poison had killed all of the
caterpillars. Later, in April, 1899, the webs were placed
in a warm room and isolated, with the following results : —
243 webs on pear :
April 26,
April 27,
April 28,
April 29,
April 30,
4 webs yielded larvae.
25 webs yielded larvae.
5 webs yielded larvse.
- webs yielded larvje.
- webs yielded larvae.
34, or 14 x^er cent.
A number of webs had also been gathered under exactly
identical conditions from certain large elm trees that had
been sprayed as thoroughly as possible at the same time
and with the same strength of poison. These webs 'yielded
many more larvae as will be seen by the table below : —
70 THE BROWX-TAIL MOTH.
237 webs on elm : —
A2:)ril 26,
April 27, . . .
April 28, . . .
April 29, . . .
April 80,
101 webs yielded larvae.
10 webs yielded larvae.
12 webs yielded larvae.
- webs yielded birvoe.
3 webs yielded larvae.
126, or 53 per cent.
These figures show clearly that fall spraying is not an
exterminative method, probably for the reason that some
of the insects enter the webs early to hibernate. It is also
Yery interesting to notice the difl'erence in the efi'ectiveness
in the spraying of large and small trees. The pear trees
were easily reached by ladders, and thoroughly sprayed.
On .the large elms thorough work was also attempted and
much time and labor spent in spraying them, but the results
were only one-fourth as satisfactory. These figures also
have a wider simiificance, in showing us how difficult it is
to get entirely satisfactory results in spraying large trees.
Municipal AVork.
The advent of the brown-tail moth in Massachusetts and
its gradual distribution in thickly settled districts gives
another excellent illustration of the interdependence of all
citizens in a community where matters of public good are
at stake. AVhere the moth occurs but scatteringly, its
ravages are slight and the pest is easily controlled. The
case is far different, however, M'hen the insect is numerous ;
one single pear or apple tree on an estate may carry from
one to two hundred webs, each Aveb containing, on the
average, two hundred and fifty caterpillars. The insect
spreads readily in the taller shade trees, from which it can
only be cleared at a great expense. Even if the property
owner succeeds, at the outlay of much time and money, in
freeing his place from these insects, his labors are unavail-
ing should his neighbor, through ignorance or carelessness,
allow the trees on his estate to remain badly infested.
"We have seen repeatedly in the metropolitan district
numerous illustrations of the annoyance and damage thus
caused by the neglect of one property owner to clear his
THE BROWX-TAIL MOTH. 71
trees from the insects after his neighbors had destroyed the
webs on their own trees. This matter of web destruction
is often an expensive undertaking. Many property owners
can ill afford it ; certainly tenants cannot, as a rule ; while
the non-resident owner is very apt to neglect this work.
Clearly, then, this is a case where co-operation is a neces-
sity, if the moth is to be held in check ; and, lacking State
supervision of the work, municipal enterprise offers the
most promising means of relief.
Under our present laws, municipal officers have the
power to enter on private estates for the purpose of sup-
pressing dangerously injurious insects ; and it is the
opinion of the writers that the control of the brown-tail
moth clearlj^ falls within the field of legitimate municipal
enterprises.
This pest is certainly a menace to the property and wealth
of citizens, while by its attacks on street trees it directly
destroys the property of the city or town where it occurs.
The good of the community demands that the brown-tail
moth should be suppressed, and in no way can this be done
more economically than through the direct and systematic
work of some municipal department, preferably the one
having in charge the parks or streets. In this way all tax
payers in a community, sharing, as they do, in immunity
from damage by the moth, also share in the cost of its sup-
pression.
A campaign against the brown-tail moth is best begun in
the fall or early winter, preferably in December, after the
leaves have fallen from the trees. A preliminary scouting
or examination of the territory is always of advantage, as
showing where the moth is thickest, and the amount of work
necessary for its suppression. If the municipal appropria-
tion is of adequate amount, the whole region should bo
carefully worked over, and all webs destroyed, in order to
prevent the local increase of the moth and its further spread
the following summer. Where, as is too often the case, the
appropriation is a limited one, the worst infestations should
be attended to in a thorough manner. It is but follv to
spend money clearing tall street trees from the webs of the
72 THE BROWN-TAIL MOTH.
caterpillar while in adjacent yards there stand pear trees
bearing hundreds of webs within easy reach. Dense infes-
tations should be stamped out first of all, to prevent a
serious caterpillar outbreak the following year, with its
consequent damage to property and persons. Later on, the
more thinly infested districts should be worked over so far
as funds permit.
From three to ten men can be profitably employed in a
gang, while several gangs may be placed under one foreman
or inspector. Maps showing accurately the location of the
principal infestations, together with the streets included
therein, should be in the hands of the foreman, in order
that a proper record of each day's work may be made, and
thus preserved for future reference.
The importance of destroying the moth on private estates
as well as on street trees has already been pointed out.
Usually where this has been attempted by municipal authori-
ties it has met with the approval if not co-operation of prop-
erty owners. Since, however, previous to 1902 there was
no law authorizing municipal authorities to enter private
grounds for this purpose, a special act conferring the desired
authority upon them seemed desirable. The following law
was enacted Feb. 5, 1902 : —
[Chapter 57, Acts of 1902.]
An Act to authorize certain city and town officers to enter
UPON private lands for exterminating the brown tail
MOTH AND other SIMILAR PESTS.
Be it enacted, etc., as follows :
Section 1. Whenever the brown tail moth, the ehn-leaf beetle,
or any other tree or shrub destroying pest shall be discovered in
any city or town of the Commonwealth, such city or town, by the
municipal officer or officers to whom the care of the shade trees
in the streets or roads of such city or town is or may be intrusted,
may enter upon private land for the purpose of investigating said
pest, and may adopt reasonable measures to prevent its spread
and to secure its extermination.
Section 2. The owner of any land so entered upon, who shall
suffer damage by such entry and acts doue thereon under the au-
thority herein given, may recover the same of the city or town in
which the lands so asserted to have been damaged are situated,
THE BROWX-TAIL MOTH. 73
by action of contract; but any benefits received by such entry
and the acts done on sucli lands in the execution of the purposes
of this act shall be determined by the court or jury before whom
such action is heard, and the amount thereof shall be applied
in reduction of said damages.
Section 3. Whoever shall oppose the entry aforesaid, or ob-
struct the performance by the said local authorities of said work,
shall be punished by a fine not exceeding twenty dollars for each
offence.
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